What an experienced instructor he is. He explains everything in a way that a 4 year old understands and can explain as well. * Love your videos Alec, you contribute to overall knowledge of divers from all over the world!
Biggest difference is the surface interval required before dive 2. On recent trip my buddy was on nitrox 32 and I was on air. When we got in the water for dive 2 after a surface interval of a couple of hours, my max no-stop time was 24 mins, his was 94 mins!
Excellent video Alec, as always!!! I revisited it after doing my EANx certification (a couple of weeks ago) and your advice is always right on spot! I only did 4 Nitrox (31 and 32% measured from the analyser) so I am far from an expert but I did experience somewhat less fatigue. It might have been a placebo effect or something different but I did not know about this side effect after reading the comments below and told my instructor about that and he was not surprised. So, great recommendation you made... take the course... Thanks! I hope you understand that the information you teach (and that is the right word) has helped me (and probably many more) to become better divers. Understanding some things give me more confidence both, outside and inside the water. For that, thank you very much indeed!
Love all your videos, you're quite the character. I just read my nitrox lesson book and I'm taking my classes next week in NJ, checkout dive in Key Largo in February.
6:15. I agree that of course "nitrox" reduces your maximum operating depth, so it doesn't let you go deeper in that sense. But it definitely extends your bottom time at 30 meters to be using nitrox, so to imply that it NEVER extends your bottom time is also misleading. The truth is that it definitely extends my bottom time on a regular basis because it reduces my nitrogen tissue loading, so when that is the limit, I benefit.
No argument. My beef is with divers or store owners who SELL Eanx on the premise that they can stay down longer and go deeper. That's NOT the reason to use Nitrox as you know. Setting aside all of the possible benefits of Nitrox, proven and supposed, the reason to use EANx is to increase diver safety. Take care and thanks for watching. Alec
Dear Alec Thank you very much for the wonderful videos and valuable infos! Would you consider coming to Egypt and give some lectures on scuba diving in Sharm El Sheikh and Dahab in Sinai peninsula? We have wonderful diving sites up there on the Red Sea... I wish a happy new year to you and to your family Hisham
You hit the high points and disadvantages of enriched air. Is the more or less? Yes but, your not teaching a class which you stated. I’ve been diving for some time but, I enjoy listening and also pick up things I forget. Thank you for your service to the industry👍😄
Thanks for grasping that fact Golden boy. Some readers are concerned because I don't cover ALL the points in an issue nor explain in great detail a particular concern. I'm compelled to keep this videos as short as practical - less than 10 minutes is the goal. It's definitely NOT a classroom lecture. I am trying to introduce diving topics or ideas that a diver may not have thought of. It's supposed to be an introduction, a synopsis if you like, of the subject. Take care. Alec
My kids and I are taking the course now, reading up before class. The main thing I'm noticing is whether or not we ever dive Nitrox, is the class really digs into the physiology of what nitrogen and oxygen does to our bodies and how it works. We're gaining a much better understanding of breathing air, diving and all it's effects.
That is something I've discovered over the years Scott. Learning about diving open your eyes to many other things. Good luck and enjoy diving with your kids. I have dived with all 4 of my kids and so far, 3 of my 6 grandkids. There's a possibility that I will be able to dive with a great-grandchild! Alec
Happy new year Alec. I love your video's. You explain everything another way and give more information then at courses. I hope you can make these video's a long time
Thanks. I'm hoping to be able to do so. There are lots of topics. I just have to keep up my energy and my interest. Comments like yours helps with the latter. Alec
Hey Alec! Thanks for all the great info! As I’m getting older,unfortunately, I’m looking into nitrox. My question,is it ok to use my Scubapro Mk 5 from the 1980’s with nitrox? Can I go back and forth from nitrox to air with the same reg? I remembered that when nitrox first came out I was told you needed a dedicated nitrox reg. What the right thing to do? Thanks a lot sir!
Any regulator that has been serviced in the last 10 years should have EAN compatible o-rings and lubs. Watch my video S10E02 Is Tank O2 Cleaning Necessary? It should answer your questions on tank and reg compatibility. Thanks Pete. A.
Nice video. A bunch of us took the Nitrox course thinking we could stay longer or deeper. After the course, we realize that wasn't gonna happen. Anyway, water under the bridge, but it's good to know that as we get older, we may have the option to use it, if we plan on more dives per day. Thanks.
@@AlecPeirceScuba_SeaHunter true ... in my case though it was due to inexperience while in my open water and I had try to fin to much too fast to reach my buddy diver and then at the surface I had to remove my mask and reg and then snorkel also as nothing was giving me enough oxygen to recuperate ... I almost passed out ... I have learned then the importance of good shape and to stay calm and not rush in the water ;)
Great video Alec. I think Divers should know that nitrox is only safer if you do not dive your gas Ndl limits or you will have the same nitrogen gas loading as if you were diving air - More bottom time but the same gas loading.
Solid idea. I use NITROX often if diving deeper than 50' I'm old and have quite a bit of scar tissue. But I usually dive air tables when using NTROX. Double safety. Alec
Hi Alex, incredible videos and I appreciate you sharing it all with us. I’m a fairly new diver and booked my first live aboard trip. Any pointers on what to bring on a live aboard trip.
Money! No. Just kidding. Other than tips and maybe alcohol, one benefit of a Live-Aboard is that everything is included. I suggest that you have DAN Diver insurance, as much of your own gear as possible (at least mask, fins, snorkel, reg system and a computer) and a relaxed attitude. You are going to be spending a week in confined quarters with a group of strangers, some stranger than others. You need to be able to look away and not let things bother you. relax, laugh and enjoy the diving. Alec
Alec Peirce Scuba thanks Alec! I will keep all that in mind. I did just purchase all my own gear and plan on bringing it. Keep up the amazing videos. I’m getting my 14 yr old son certified in hopes of giving him a lifetime of adventure. He and I watch your videos. The history of things you teach help him understand the concepts of his class!
I've just come back from a weeks liveaboard in the Red Sea (Egypt). A liveaboard is the perfect time to be diving nitrox. We couldn't have done the dives we did on air without exceeding our no deco limits.
I just got my Open Water Diver certification... and I got my Nitrox certification at the same time. I got to use Nitrox on the last of my Open Water course dives!
You will enjoy it a lot and if you ever think it does not make a difference in how you feel after a dive, use air once and see how tired you are. Welcome to the scuba world.
You get it wrong. Nitrox ist not about the higher amount of oxygen, but the reduced amount of nitrogen. Nitrogen is responsible for fatigue. Adding oxygen is just the cheapest way to get rid of it. Therefor many holliday locations offer "Nitrox for free" because, you get to dive more often.
@@Skunkiboi I can see what you mean with offgassing during deco but I can't rule out that being highly saturated in O2 has no positive physiological effects at atmospheric pressure. If you have a medical journal that covers the effects of Nitrogen gas on fatigue, I'd love to read it because I'm pretty sure my body would be infinitely happier getting O2 at the surface than something like heliox which would also displace the amount of nitrogen in the mixture. It's there to displace nitrogen, yes, but I'd posit that it also has its own physiological effect-I'm glad to be shown otherwise.
@@YuriyDel There isn't one. There have been a couple of studies that were inconclusive. The "less fatigue" is a placebo effect that many believe works for them.
Alec, could you do a tec tips on full face masks. I'm in the process of getting cert and of course so much to choose from, been watching tons of your vids, any updated gear recommendations for absolute beginners, for those of us on a budget. Could you also explain the dive tables. Thanks for your hard work.
I can do a Full Face episode. I used to teach Full Face. It's not a widely interesting topic. Full Face is not common in recreational diving. There are really only 2 suppliers and they are both excellent. Take care. Alec
mudman0572- if you're interested in FFM and safety, i recommend the Hollis MOD-1. i'm a recreational diver but i purchased a MOD-1 2 years ago. i absolutely love it (except for the limited Peripheral vision) and i bought it because of the safety factor. it's considered a "Double Half Mask" because it's possible to remove the "Pod" (2nd stage) from the mask without having to Doff the entire mask. so, in an Out of Gas situation, you simply detach the Pod and insert second 2nd stage to your mouth OR attach 2nd Pod to mask. (of course, if you have a Switch Block, you can switch gas on any FFM without Doffing mask but that's another story. i recommend this video ruclips.net/video/OuaQdQ56-iI/видео.html if you'd like to see the Hollis MOD-1 in use. (i actually talked with this guy before i bought mine. he's a very nice guy). good luck!
Alec, I recently went on a guided dive with a new diving club, and the tank they gave me had a standard Nitrox label on it. "Okay," I said, "I'm Nitrox certified. What percentage is this," since the tank was not labeled with eanx info. "No no, it's not Nitrox," they responded, "it's actually air." We continued to discuss my surprise that they'd give me a Nitrox tank with regular air inside, especially considering the extra work they may have to do to recertify this tank as oxygen-capable now that it has been used to a lesser standard, as well as my discomfort that they didn't take the Nitrox label off and wondering about what other logical steps they may be skipping over... Ultimately, I asked to use their O2 analyzer to confirm it was @21%, and the dive master who had handed me this Nitrox-labeled tank swore up and down that he knew for sure that it was air and there was no need for me to test it. Finally, after considering the dive profile (
I own 6 tanks i keep 3 of them nitrox certified and the othe 3 for regular air. I ues all 6 with regular air. If i want to dive nitrox than i use my nitrox tanks. Common practices with my other dive buddies.
When you get a tank from a shop you can always ask them to analyze it in front of you. As a matter of fact a nitrox tank should be analyzed by the blender at the the of mix and then by the diver prior to diving.
"2. I decided never to rent an "actual" Nitrox tank from them, because I no longer trusted them to treat their Nitrox tanks with the additional caution they deserve. Does this seem like a good conclusion for me to draw?" No, it's not a reasonable conclusion. Why would the tank being filled with regular air make you think they treated the tank any less carefully than if they filled it with Nitrox? I wouldn't accept ANY tank, Nitrox-labeled or not, from a shop that I thought might be filling my tank with oil-contaminated air, or in any other way using "less caution" when handling it. Regular air is, practically speaking, just EAN21 Nitrox if you think about it.
Just a point or two - in EANx the x stands for the fraction of oxygen in the mix. You may see it written out as EAN32 for a 32% O2 nitrox blend. While we often call it Oxygen Enriched Air, the added oxygen is not the primary benefit, but it the gas used to displace the nitrogen, the inert gas, in the mix. The N2 is the limiting factor from a decompression viewpoint. The body does not absorb O2, it metabolizes it, which is why it does not have a negative impact on your dive time. Fat tissue is considered a slow tissue in the body, it has less circulation than muscle and absorbs inert gas slower. It also off gasses slower.
yes, nitrox is usually made to allow longer dives but you may reach the O2 toxicity limit faster than narcosis with air and tech dives its used for deco stops to reduce time
When we go to a place like Bonaire or Roatan we always use Nitrox. We like to get in a least 4 dives per day and usually 5 during the week. As some people pointed out, we found we had less fatigue at the end of the day than when we used air. Although, Nitrox limits your depth there is rarely a need to go below 70 ft to see most things. If using a decent surface interval we found there no issue with either nitrogen build up or oxygen toxicity after the 5 dives. Most places in Bonaire will give you Nitrox or air for the same price so the Nitrox certification is definitely worth it.
@@fredyg.1561 We were mainly around the west end. I have a RUclips channel, Virusking, where I list each Roatan dive site along with a video of our dive. We also did the shark dive on the other side of the island. I think we got 21 dives in that week.
The Enriched Air Nitrox course is one of PADI's most popular and you can take it anytime. In fact, since it is an academic-only course, no pool or open water, you can take it before you are certified and then become certified during your open water divers. Have fun. Alec
Recalling from my recent PADI Nitrox course training, I think you're partly right as that's the net effect of reducing Nitrogen on-gassing... however Alec hints at the major concern which is Oxygen toxicity.... both immediately because of depth (partial pressure of Oxygen exceeds safe levels), and accumulation/build-up over time, leading to Central Nervous System poisoning...hence the possibly shortened later dives. It's a balancing act as always.. no silver bullet.
I think it's a semantic argument. If you hit your NDL before your turn pressure then nitrox extends your NDL and therefore your bottom time. If you're like me and breathe down your tank well before your NDL, it won't help because your breathing rate stays the same so you'll still run out of gas before NDL. Similarly if you were planning a dive to a certain depth on air, but the NDL was too short to make it worth your while, **as long as you don't violate the MOD of the mix**, you'd get more time at that depth which might put it into the realm of "ok it's worth my while now".
Yggdrasil42 Why use a side mount? You can use Doubles, twin 72s, twin 80s, twin 85s, twin 100s, and get better performance than with side mounts. And as for cost, side mount diving costs just as much as doubles :)
Jason Wheeler You're right, but Oxygen Toxicity takes quite a while to build up. Even on days with 3 or 4 dives (like on a liveaboard) you won't run into it. So the extended bottom times far outweigh that downside.
EAN reduced the amount of nitrogen in a divers system to allow longer dives but causes a reduced depth. It's a trade off but EAN also makes a diver feel less tired from less nitrogen. The Enriched Air course explains everything you need to know. A
Alec, is it true that using the Nitrox I can consump less gase mixture? Because every breath that I take has more ppo2? Is there any studies about how we metabolate oxigen in the different gase mixtures with different partial pressure of gases? Great video, Alec.
That may seem sensible but it's definitely not the case. When you inhale, the same amount of air by volume enters your body on every breath, limited by your lung capacity. Then your body consumes oxygen as required by your body functions. If you are cold or working hard, your body requires more oxygen so 2 things happen - you breath more rapidly (more volume) and your body consumes more oxygen. Interestingly, the amount of oxygen that is used from each breath doesn't vary much. The body gets most of its required extra air from the increased rate of breathing (more volume). This can be shown by working had on a 20% mix and noting the increased breathing required to meet oxygen demands and then comparing that with working hard on a 32% mix. In both cases, you need to breathe faster to meet demands and the increased rate is similar. Having a higher oxygen percentage does not allow the body to not breathe faster to meet demand. So whether you are breathing a 20% mix or a 32% mix, the body only requires a fixed amount of oxygen to function and that's all it uses from that breath. If you were breathing pure oxygen (100%), only a small fixed amount of that oxygen would be used on each breath. The principle of rebreathers confirms this and that physiological process is the same regardless of the PP. Partial Pressure is not related to a bodily function. It has nothing to do with the respiratory function. It is a physical or physics function and only affects the rate that the gas is dissolved in the blood. Dissolved gas, nitrogen, oxygen or otherwise, as in decompression sickness, is not used for respiration. Bear in mind as well that the body does not respond to oxygen. Your body does not know (nor care) how much oxygen is in the breathing mixture. It responds to increasing carbon dioxide from the respiratory process. You have no idea what the oxygen level in a breath is. You only know when you have used as much as required and you only know that because of the increased level of carbon dioxide. Also realize that the benefit from the use of EANx is NOT from the increased oxygen but from the decreased nitrogen. Using EANx increases diving safety by lowering the risk of decompression sickness. This is a non-scientific explanation of the respiratory process. There are many factors involved in the process. However, it's a pretty accurate and clear explanation of how it all works. I hope that helps. Alec
@@AlecPeirceScuba_SeaHunter Alec, you know, I'm really have heard from several divemasters like Nitrox has the advantage in term of gaze consumption. I was doubt. I will show them your post. Thank for clarification))
Air consumption will be the same. This has actually nothing to do with the amount of oxygen in your body or the partial pressure of it. But the amount of CO2 that's build-up in your body. This triggers your breathing.
@@AlecPeirceScuba_SeaHunter so you can't hold you breath longer breathing say pure O2 because of the CO2 build up ? how do freedivers who pack their stomach with air do it then ? seems sensible that Nitrox higher oxygen would allow you stretch your air longer if you hold it (which I know you're not supposed to while diving but that's really because of depth changes).
@@alaind831 Free divers take deep breaths before diving to expel as much CO2 as possible. That way their brain doesn't feel the starvation for air, allowing them to stay down longer on one breath.
1 second. There is no mix time for nitrox as its fully mixed when ready for diving. Watch S08E21 Now Is Nitrox Made? and S11E19 Scuba Myths: Tank Air Goes Bad. These two will answer your questions ND.
Alex, while I’m not sure there’s science behind it, you did not mention that many people feel Nitrox equals less fatigue after diving. Whether it is a placebo or not I feel better after Nitrox dives. Your thoughts? Thx
D H There's some science behind it. A) An increased oxygen level in your tissue means that less energy will have to be spent to do the same amount of work B) Less nitrogen in your tissue
D H there is less nitrogen in the mix available for uptake during the dive and subsequently less nitrogen to eliminate post dive which more likely results in a feeling of less fatigue post diving versus an energy boost from a higher oxygen levels relative to air
DAN has studied and proven that there is no proof that Nitrox reduces tiredness. Nitrox can actually increase oxydative stress. www.alertdiver.com/?articleNo=1836
If I have a tank that has been cleaned, prepped and labeled for nitrox, and want to fill it with regular air, will the tank and valve have to be cleaned again to go back to a nitrox blend?
@@rickkinney2544 If they offer nitrox, they'll be pumping extra clean air. The majority of places will be delivering this, just check when you give them your tank for filling
Yes but you can always go EANx 21. It's still Nitrox but at the same blend as surface air-assuming you'd do this because you were doing a deep dive and needed the MOD thereof. That's if you want to avoid having to get everything cleaned again.
If your dive store has EANx, it will also have OCA. OCA is Oxygen Compatible Air - simply air that is certified to be clean for Nitrox use. It is the air that they use to make their Nitrox blends. If you use OCA in your Nitrox tank, it does NOT have to be cleaned for future Nitrox use. Ordinary breathing air may not be suitable for Nitrox use. Some stores charge extra for OCA. Good stores do not. While there may be a slight additional cost to the store for making OCA, they have to have there anyway, whether you buy it or not. That extra cost is covered by the Nitrox users. Take care. Alec
Is it the high body fat and low skeletal muscle (often happens with age) that causes it? What if one is old but not fat with high percentage of skeletal muscle? (eg 50% muscle - old but lean and muscular)
Hi Alec Can you tell me how to calculate the amount of exposure to oxygen from multi-depth dives As the tables are based on the fixed depth according to the values of exposure And the second question does it appear in the Maris Smart Air computer? the % of exposure ? The third question: i know that nitrogen absorbs less than oxygen in diving usually. If that is the case, does oxygen have the same property, or is it that when it reaches the upper limit of 1.4, we can only go up to a higher levels and drop quickly? I hope the question is correct If you think it is appropriate to explain it in a video, I would be grateful As our trainer died, he made a technical dive at 65 meters, then after he finished the dive after 20 minutes and at a depth of 35 meters, he wanted to change to the Nitrox 37 cylinder, so he mistakenly replaced it to the cylinder with a concentration of 80, where according to the words of those who were with him, the oxygen was almost at His ascent reached 1.6. When the error occurred, the ratio shifted to 3.55. Can you explain what happened? Thank you for your wonderful communication.
From your description I understand the consequences of the O2 partial pressure of 3.55. Way to complicated to explain and I don't want to share partial info that others may use incorrectly. Best thing is to post a question to the tech experts on www.scubaboard.com. You will get lots of info on this incident and explanations/links and help on the question of multi-depth diving. Hope this helps and safe diving.
Alec, first of all thank you for your videos. My question today is that I've been watching different dive configurations, and I see some parts in Europe use a 7' primary, and then they have there back-up on a bungee around there neck. I would just like your opinion on the matter because it seems to me that the primary should never leave my mouth. Just wondering why they choose that way.
The person who is out of air needs a working reg immediately. You know the one in your mouth is working, so that is what you should donate. Seven feet allows the divers to swim comfortably side by side or inline while sharing air. Having your backup under your chin ensures it will not be dragged in the mud, you can get to it quickly and if it ever leaked, you would know it right away. It's a much safer way to dive than having a 40" hose between two divers or trying to breathe from a second stage that also works as a BC inflator which needs to be free to operate during an ascent.
Pacificcoast has provided an explanation for the use of the Hogarthian regulator set-up (named after the guy who promoted it). I personally am NOT a fan. I see no reason for it. The standard set-up (so-called because it works well for 90% of all divers) is as close to perfect as you will find for diving and for handling emergencies. Changing things drastically is not good. Having said that, there is an application of the 'long hose' set-up that could be valuable. It is in fact, the impetus for its development but pacificcoast either didn't know that or missed it. If a diver and his buddy are in a cave or other confined environment where a diver may not be able to reach the normal octopus, the long hose may be useful because it can be passed back through the legs or down the side of the diver to the diver in trouble. Several of pacificcoast's comments are simply not based on fact or experience. 1. no diver would enter the water if he wasn't sure his entire set-up was working, maybe especially the octopus 2. 7' is much too long. 3-4' is good. You need to be able to reach the diver but not so close as to have him interfering with you. At 7' you can't reach him and you have a lot of twisting hose to contend with. Not fun. 3. he's right that you know the one in your mouth works, but if you're not so sure about the other one - why would you give it away? 4. the octo should be attached right in the middle of your chest. It won't be dragging in the mud and is instantly available by either diver I have discussed this issue in several other videos as well as the question about BCD-mounted safe seconds (which, like pacificcoast, I also don't like). I hope this answers some questions. You can find lots of information (too much) about the Hogarthian set-up online. Take care. Alec
I dive in this configuration. (located in Ontario) it all comes down to preference. I have had to share in low air situations before and i kinda like that who i'm handing off to isn't right in my space to complete the dive. the extra length gives a buffer zone. this does not mean that you wouldn't still link up while you are sharing. just means that if there is a little drift apart for some reason the Reg isnt yanked from their mouth.
The reason you can't go deeper with nitrox is oxygen toxicity. The higher percentage of oxygen in your tank means lower maximum operating depth(mod). A 21% of oxygen tank has a MOD of 187 ft. while a 32% has a MOD of 111 ft.
Correct. I plan to elaborate on the disadvantages of Nitrox in a future video. EANx (Nitrox) can be very beneficial but it's not the panacea or cure-all as some divers think. Alec
It all deals with the increased ppo2 %. Recreational divers can go up to 1.60 ppo2 on nitrox 32. Also it's more then just ppo2 it's also a time that your breathing that ppo2. Took my nitrox class got my nitrox endorsement. I recommend nitrox class for any diver. Way more to it then I'm typing but check it out. You'll learn alot
When I first went and got certified for Nitrox (over 20 years ago) my diving buddies and local shop said I was going to kill myself with that stuff. After they actually researched and learned about it, it didn’t take them long to change their mind.
A typical early experience with the dreaded 'Voo Doo Gas' as Skin Diver Magazine first called it. Today EAN is second to u/w photography in new certifications. Even divers can adapt to new ideas sometimes.
this was a little misleading. Nitrox certainly does help you stay longer if you are doing repetitive dives and don't want to have deco dives (what most rec divers do). As matter of fact if you do 2+ days boat dive trips and/or 6+ dives a day it might be the only way to not sit a dive out and have very long surface intervals... sure it's not giving you more air so you can still run out regardless.
Diving EANx allows faster off gassing during surface intervals as the nitrogen load is less in the different tissue compartments. So you are correct but Alec was referring to diving a dive at a time and how with certain mixes, you can actually have less time; example EANx 38% and deeper depth (>100 ft or 33 m) and your dive time will be limited compare with air.
@@rgorji even a single dive at common rec depth of 60ft (I'm not talking about depth where Oxygen poison is an issue as Alec target audience are rec divers), 32% nitrox will let you stays longer than air without having to deco - people might run out before that, but you can have a longer no-deco dive time. at 100ft, it's significantly more (like 50% more no-deco time). Also missing listed benefit of Nitrox is that some feel less tired after dives (less nitrogen in body).
Don't fight boys. You're both right. This is the first of a couple of EANx-related episodes. I wanted to dispel some misconceptions about the use of Nitrox, primarily that it allows a diver to ignore dive tables and stay down as long and deep as he likes. Yes. There are divers who have been told this and who believe it. There are many instances where, even on a single dive, benefits arise from the use of Nitrox. I have answered some questions about the 'less fatigued' issue Alain. It's not yet been defined as a proven medical benefit. But, as I've said, if you feel less fatigued after a dive using Nitrox, good. Thanks for watching guys. Alec
@@AlecPeirceScuba_SeaHunter yes but in your video you could have said "Nitrox, with it's most common 32% mix, will allow you to have longer no-deco times and shorter surface intervals as there is less nitrogen for your body to absorb, but will limit how deep you go as oxygen becomes toxic at depth". Since you skipped the more technical aspect....You only focused on deco sickness - which is important, but indirectly implied if you no-deco times are longer but you still dive shorter dives, there is a larger margin of safety. Someone watching this video might just skip learning more about nitrox (unless old/overweight).
I was on Bonaire a few years ago and I noticed all american divers where using nitrox and dutchies did not. Nitrox isn't that popular here in Netherlands , I also do prefer normal gas to keep things simple and I can use any fill station I want. We even do have unmanned self filling stations for normal gas over here in Zeeland, Netherlands.
Nitrox is a bit of a fad over here. Many divers use Nitrox because their buddy does, or it looks cool, or they think it makes them better divers - none of which is right! For most divers and most dives, normal air is perfect. I tried to set up a 24 Hour Fill-It-Yourself air station at my store but didn't get it completed before I retired. In the US (I'm in Canada), I'm sure it would be impossible for liability reasons. The first diver to hurt himself or get a short fill would sue the dive store and it's over! Take care. Alec
@@AlecPeirceScuba_SeaHunter I want my buddy to use the same mix as I am, so we have the similar no stop times, and/or decompression profiles. Personally I find the most benefit with nitrox and square profiles below 70ft. A multi-level profile, like a Cozumel wall dive, has enough things to see at shallower depths that you typically don't need nitrox unless you are doing more than 4 dives a day. I do know of one self service fill station in the States, of course it is in cave country so I am not sure if it is because they march to the beat of their own drum or simply that there is no demand.
Tables do not but dive computers have a 'conservative' factor to compensate for a lot of issues: age, health, married! Using a more conservative setting changes the algorithm to reduce dive time and other factors for a safer dive is your not in Navy Seal condition (that's me). Every modern computer has this so reading any dive computer manual will give a detailed explanation. Take care Danny.
@@AlecPeirceScuba_SeaHunter Very good thank you for the reply. I have a Sherwood computer on order but have yet to download the manual if it is available online.
Variations in which gases do what are the premise of nitrox, I was lead to believe that if you used Nitrox then since you inhale less nitrogen, your decompression rate for your depth would be longer - enabling a longer bottom time - but since oxygen is toxic enough to kill you below 8 meters at 100% (trivia from an old rebreather documentary I haven't had debunked yet) your depth limit - or the depth at which you should under no circumstance should you exceed - is shallower. I knew a guy that dived with Nitrox in Thailand and he did have a fair bit of body fat (and had a stint in a decompression chamber) so I guess that confirms that hypothesis! The result is that if you use enriched air - you can stay at your maximum depth with less worry of DCS and fatigue, but more risk of oxygen toxicity - which is different from nitrogen narcosis only in that it doesn't get you drunk but rather floods your nervous system and risks a more fatal reaction (seizures, blindness, sudden lack of awareness and death) instead of getting you a little giddy and forgetful. It's still a form of gas narcosis, it's just that your risks change form and there are different calculations you use to calculate your decompression stops (many newer dive computers have adjustable nitrox settings) but of course, just watching your bottom time is not enough to keep you from running out of air! A breath is a breath and at whatever depth and the same starting pressure, good breathing control is the only way to prolong a dive! (Also, between you and me, I don't mind the fatigue too much, it makes for a great night's sleep!)
Oxygen toxicity doesn't become an issue until the PP (partial Pressure) of the oxygen reaches 2 atmos (approx 30 psi). Using normal air (20% oxygen) that wouldn't occur until the diver gets to over 300' - not likely to occur. At 300', oxygen toxicity is the least of his worries! Using an EANx mix of 32%, oxygen toxicity doesn't pose a problem until he reaches 200'. Again, not the real concern. So, oxygen toxicity is not a reason to avoid the use of Nitrox. It is addressed in Nitrox tables and with the use of a computer anyway. Most modern dive computers have Nitrox setting. You simply enter your mix and the computer takes over. It's true that I always sleep well after a good day of diving, crazy gas or not! Take care. Alec
Oxygen Toxicity is a function of partial pressure, and time. As noted by Alec, you doesn't become instantly fatal until you are at a PPO2 of 2. At every other PPO2 there is a time component from 45 minutes at 1.6 to 720 minutes at 0.6 (per the NOAA Diving Manual). There are long term exposure limits, but those aren't that relevant unless you are a commercial or scientific diver. As far as narcosis, Oxygen is more narcotic than nitrogen, that is why narcosis is never mentioned as a benefit of Nitrox, if you want to reduce narcosis once you get below 100ft/30m, it is time for Trimix (which incidentally is why some DIR agencies require Trimix below 100ft). You are right for many cases air time is the limit of their diving, for me I have reasonable SAC rate for my age, and sex, so for deep dives I am more often limited by my no stop time. EAN32 at 100ft I get 30 minutes vs 20 minutes for air (per the PADI RDPs). So for $2.50 more I get 50% more bottom time. And my computer handles all the no stop times, and the decompression profile if I stay long enough incur a mandatory decompression stop. And if my primary computer breaks, my secondary computer does all the same too.
Well I guess Alec is right, there is allot to learn about alternative air mixes and they all mean different styles of diving - I guess that's why technical diving is so much of a standard of its own!
@@Teampegleg > EAN32 at 100ft I get 30 minutes vs 20 minutes for air (per the PADI RDPs). So for $2.50 more I get 50% more bottom time. which is why I mentioned Alec video is misleading as most rec divers will get more non deco bottom time with Nitrox (if air time ins't the limit already). I too often get limited by no-deco, not running out of air, especially repetitive dives... Maybe my cobra is too conservative, but I'm also not as young now. Alec: > Using an EANx mix of 32%, oxygen toxicity doesn't pose a problem until he reaches 200'. Again, not the real concern. My Suunto cobra with default 1.4 gives me 114ft at 32% if I recall (I can choose up to 1.6 to increase that depth) which is quite a lot less than 200' you mentioned (at 2.0x ?)
@@alaind831 The Cobra is pretty conservative particularly on repetitive dives, as the bubble model doesn't like repetitive dives. A dive computer that uses a pure dissolved gas based model, like the Buhlmann models, might give you a bit more no stop time on repetitive dives.
Alec, really enjoy all of your videos, keep up the great work! I have only been diving since March of 1974, so I am certainly a neophyte compared to you. Certified in 2007 in EANx, my instructor and I had many conversations about potential oxygen toxicity and its scary, sometimes lethal effects. O how I do love Nitrox, because just one of its benefits for me, is that most the time I feel better and more refreshed after each dive. For my shore diving I exclusively use 40%. It gives me an MOD of 82'. As the years roll on however, I become more, and more concerned and literally afraid of oxygen toxicity. Because according to my instructor, once O2 toxicty happens, most of the time a person goes into convulsions. I am a health care provider, so I do know the anatomy of the body quite well. And once one loses control of the diaphragm, death quickly ensues. My 2 questions to you are how best to eschew the pernicious state of oxygen toxicity, and once one is unfortunately in that situation, what is the best remedy for it? Anxiously looking forward to your reply........
When nitrox first was introduced to diving many called it 'Voo-Doo' gas. They had the same prejudices against it as single hosed did to the established double hose crowd (we know who won that). Today EAN is almost the same as u/w photography as the most popular specialty to get. Thanks for the history lesson from another 'stone age' diver.
Cons: more expensive, higher risk of fire/explosion on regulator first stage and be ready to accept a shorter maintenance interval on your reg. If your buddy not using nitrox will end the dive sooner.
Possibly but in 50 years in the dive business, never had an explosion in my shop or any nearby. The last point is probably the most common problem but getting EAN certified is easy so get your buddy on board. A
I think oxygen toxic is a scary thing!! because once it did happened ,you probably don't even know and it doesn't matter what in the book said...because when you are diving ..there are so many things to distract you more than just notice on yourself (and how your body feel ). I am a Nitrox certificate diver, but honestly... until now I still can not find a very good reason to keep using Nitrox , Nitrox cost more money , can't go too deep too long time , everything depend on dive computer, awful chance to get hit by Oxygen toxic. Extend diving time to stay longer underwater is not match to the fact (in my case) that we dived always with a guide and group, there for meaning of we come up all at the same time. ...not to mention about ...shorter surface interval time... :( because we all diving as a group which is not everyone prefer to pay and using Nitrox . Thanks Alec to point out this Nitrox topic.. Love your video as always.
Several gas-related issues that can affect a diver are not obvious. If you choke on some food, that's obvious. If the oxygen in your air is too low or too high, you will pass out - and not even know why or that it's happening. This is one of the problems with Nitrogen Narcosis where the most common feeling is that 'everything's OK' - as you pass out. And Decompression Sickness - you don't feel anything, until it's too late. Or Carbon Dioxide poisoning (common in diving) which just makes you breath faster and faster as you pass out. Gosh, I'm talking myself out of scuba diving!! Nope. All these problems are easily avoided. Nitrox can be useful but it too must be used properly. Take care. Alec
If you're always diving with a group and a guide (I suspect as you become more experienced this won't be the case but that's a different argument) and therefore you have the same dive profile and surface interval as divers on air, then using nitrox will increase your safety margin for DCI, you only need to make sure that the max depth isn't greater than the nitrox mixes MOD, very easy to calculate and not dependant on a computer.
Agree...he didn't really explain the benefits very well. When I'm doing 3-4 dives a day on a 7-10 day dive trip or liveaboard, I'm diving Nitrox all day because it makes me much less tired.
@@LarsSveen Are you sure you dont mean helitrox(limited trimix)? As true 21/79 heliox is pretty rare anywhere ive seen, including SoCal. Also, rebreathers make sense with the cost of helium once you start using more of it, im on an optima myself.
@@LarsSveen I figured, trimix is definitely common just really reserved for tech divers currently except for a few programs in IANTD, and I see the reason more as the same fear of voodoo gas just directed towards helium than any real concern. Even in recreational NDL dives a little helium really clears the head at 35-40m and has little risk given basic training. It should be more commonly used and accepted within recreational (non-technical) diving I think.
@@Mrich775 I know there's at least one shop down here that really pushes people to get helitrox cert. PADI now even has tech diver courses, though I'm not sure if trimix is part of that. So it seems like it's getting easier to become a rec tech diver, and get some helium blend.
As usual, it is an excellent video with an excellent explication of the product. To me I fear those mix for an obvious reason, the human body is designed to run on a gas mixture of about 20% oxygen, when you modify this mixture, nothing says that it will not cause an irreversible damage to the lungs or elsewhere in your body. As you say so well, when we become old, the sensivity to feel narcosis and develop bends is increased by an important factor BUT, as we gain age, we develop some wisdom that avoid going in trouble. As amateur diver, I prefer to stay on the safe side and to not use these mixtures even my dives are shorter.
Human body knows nothing about O2 PERCENTAGE but partial pressure. For long exposure PPO2 should be between 0.16 and 0.5 bar. For shorter exposures the upper limit should not normally exceed 1.6 bar. If you are wortied about elevated PPO2 you should not dive. If you dive to 100 ft/30m i.e. 4 bar with air the PPO2 will be 0.84 bar. If you dive with EAN32 to 50ft/15m the PPO2 is 0.8 bar. From your lungs point of view the load of the air dive is slightly higher.
Without getting into the detailed physiology of EANx, I agree with you. Increased O2 is not a danger to the body - to a point. And every body is slightly different. There is no magic formula. Long and detailed studies have shown that EANX gives the older diver an increased safety factor. Hopefully, that 'older' diver also has the wisdom to not let that increased safety factor affect his dive profiles so that it is lost. It's a bit like getting a 4 wheel drive vehicle. You see it all the time. Someone buys a 4 wheel drive vehicle and they start to drive like a maniac! They don't stop to realize that they have always had 4 wheel brakes! The drive may give them more traction on acceleration and a bit more on cornering but it doesn't help with braking at all. They can't stop any quicker. So they think they can go faster with 4 wheel drive and they do so. Now their required braking distance is increased but not their stopping ability. That's what I mean by acquiring an increased safety margin and then frittering it away! Take care. Alec
There is one more (relative) plus to having nitrox available. If there is an incident you can give the victim your nitrox bottle to breath from. 32% Beats 21% when there is no 100% around.
Yes it is, and that's why there are special dive tables and dive computer algorithms for use with Nitrox. One of the tables is a "MOD Table," [ Edit: See www.deep-six.com/nitrox/eandepthtable.jpg ] where your maximum operating depth is listed based on the percentage of oxygen. For example, when I'm using EAN36 (36% oxygen), the deepest I can dive is 95 feet. The good news is that for any allowed depth, my allowed bottom time without needing decompression is longer than with standard air, because there is less nitrogen uptake.
Perfect Brian. This is the area whereby divers get the impression that they can stay down longer on Nitrox. In specific circumstances that may be the case but that is NOT the reason nor the benefit to the use of Nitrox. It is purely a safety issue. Alec
@@AlecPeirceScuba_SeaHunter really confused about your statement above... no-deco times are longer on nitrox (using rec depth limit table listed above) and shorter surface interval - reason why many of us use Nitrox, if air supply isn't your limit, for square profiles.
Well now that I’m old and fat maybe I will waste money on it. Thank you my problem is I did commercial diving for years and not sure what the class gains me. I’ve done a lot and the dive computers are amazing(tables would limit me). I just don’t see the whys with 80 tanks I can do four tank dives which is enough(day). I don’t get in to trouble with any algorithms(most dives less than 60 ft). Diving deep I would never use Nitrox period. O2 makes me hiccup then hearing and then mental issues if I’m breathing pure o2 for extended times(chamber) deeper than navy recommendations. Just saying I think it’s a lot of marketing. I’ve been lucky over the years and never gotten sick following navy dive tables or modern computers. But thinking as I get older on shallow dives it might be best to switch to Nitrox. Thank you
Some might consider me old at 75 but I don't. Still lots of diving left in me and Nitrox is very good for these old bodies to minimize our nitrogen loads. Keep on diving which ever way you're comfortable William. Don't quit, but adjust your gear and air to our mature age! Thanks for watching. A.
Alex actually you can dive deeper for longer on Nitrox, eg multiple deep dives in one day, my first dive was 43m @ 26% I could not have completed the 2 x dives at that same depth for the same amount of bottom time on Air with out going into Deco. I know you have probably tried to simplify it but statement is correct with an explanation. 😉
Of course, there are dive profiles using Nitrox that may have extended times and depths. My problem is with divers who get Nitrox BECAUSE they think they can dive deeper and longer. They may not even know what they're doing. That's the problem. Take care and thanks for watching. Alec
Mark at 43M nitrox is really not suitable or you have just a 26% mix which will only give EAD of 40M and a 9 min no-deco time. Below 40M only trimix is suitable.
@@clarkeysam that is true. But take narcose and gas consumption also into account. You will most likely use 21 to 35% helium that will decrease no-deco a bit. But unless it's a bounce dive or dive with doubles or stages you only have enough gas with you to get 7 or 8 minutes of bottom time before you reach the point (+/- 130 bars with a single 12liter tank at 43M) where you do not have enough gas to do a emergency assent when donating gas.
@@AlecPeirceScuba_SeaHunter This seems dangerous to me for the reason you stated...the main hazard factor diving Nitrox is the lower MOD vs. a standard air mixture and the diver has to always keep this in mind as the computer would be showing erroneous information. I guess one workaround would be to set a depth alarm for the appropriate Nitrox mixture being used.
What an experienced instructor he is. He explains everything in a way that a 4 year old understands and can explain as well. *
Love your videos Alec, you contribute to overall knowledge of divers from all over the world!
Thank buddy. Glad you picked up something new.
Alec
Alec I sure do appreciate your info. my favorite channel on RUclips keep up the excellent work you made me a better diver you are the man.
Wow! Thanks Rick.
I hope you're getting some good ideas.
Alec
Biggest difference is the surface interval required before dive 2. On recent trip my buddy was on nitrox 32 and I was on air. When we got in the water for dive 2 after a surface interval of a couple of hours, my max no-stop time was 24 mins, his was 94 mins!
Reduced nitrogen load is one big benefit that is whey dive pairs should be on the same air for multiple dives.
Alec.
Excellent video Alec, as always!!!
I revisited it after doing my EANx certification (a couple of weeks ago) and your advice is always right on spot!
I only did 4 Nitrox (31 and 32% measured from the analyser) so I am far from an expert but I did experience somewhat less fatigue. It might have been a placebo effect or something different but I did not know about this side effect after reading the comments below and told my instructor about that and he was not surprised.
So, great recommendation you made... take the course...
Thanks! I hope you understand that the information you teach (and that is the right word) has helped me (and probably many more) to become better divers. Understanding some things give me more confidence both, outside and inside the water. For that, thank you very much indeed!
Thanks Guillermo for your comments and your support.
I'm always happy to hear that someone has gleaned some ideas from our videos.
Alec
British school teaches: nitrox will allow to face less fatigue (important if you drive after diving for example) and reduces a possibility of DCI.
Love all your videos, you're quite the character. I just read my nitrox lesson book and I'm taking my classes next week in NJ, checkout dive in Key Largo in February.
Great! I'm sure you'll be glad you did. Whether you use Nitrox or not, it's worth learning about it.
Alec
6:15. I agree that of course "nitrox" reduces your maximum operating depth, so it doesn't let you go deeper in that sense. But it definitely extends your bottom time at 30 meters to be using nitrox, so to imply that it NEVER extends your bottom time is also misleading. The truth is that it definitely extends my bottom time on a regular basis because it reduces my nitrogen tissue loading, so when that is the limit, I benefit.
No argument.
My beef is with divers or store owners who SELL Eanx on the premise that they can stay down longer and go deeper. That's NOT the reason to use Nitrox as you know.
Setting aside all of the possible benefits of Nitrox, proven and supposed, the reason to use EANx is to increase diver safety.
Take care and thanks for watching.
Alec
Alec, do a tech tip on painting an AL80. The proper procedures for stripping the paint of an old tank, priming and painting!
Will add it to my future ideas list, thanks.
A
Dear Alec
Thank you very much for the wonderful videos and valuable infos!
Would you consider coming to Egypt and give some lectures on scuba diving in Sharm El Sheikh and Dahab in Sinai peninsula?
We have wonderful diving sites up there on the Red Sea...
I wish a happy new year to you and to your family
Hisham
I've dived Egypt and the Red Sea.
Send me an airline ticket and I'm there!!
Take care Hisham.
Alec
Thank you Alec for another great video. Your videos are great!
Thanks for watching doc.
Alec
Thanks Alec,good info,planning on taking a nitrox course n the near future
It's a great 4 hour investment.
Good luck.
Alec
You hit the high points and disadvantages of enriched air. Is the more or less? Yes but, your not teaching a class which you stated. I’ve been diving for some time but, I enjoy listening and also pick up things I forget. Thank you for your service to the industry👍😄
Thanks for grasping that fact Golden boy.
Some readers are concerned because I don't cover ALL the points in an issue nor explain in great detail a particular concern.
I'm compelled to keep this videos as short as practical - less than 10 minutes is the goal. It's definitely NOT a classroom lecture.
I am trying to introduce diving topics or ideas that a diver may not have thought of. It's supposed to be an introduction, a synopsis if you like, of the subject.
Take care.
Alec
You're the best. Direct and to the point.
Thanks, please tell my wife that is a good thing!!
My kids and I are taking the course now, reading up before class. The main thing I'm noticing is whether or not we ever dive Nitrox, is the class really digs into the physiology of what nitrogen and oxygen does to our bodies and how it works. We're gaining a much better understanding of breathing air, diving and all it's effects.
That is something I've discovered over the years Scott. Learning about diving open your eyes to many other things.
Good luck and enjoy diving with your kids. I have dived with all 4 of my kids and so far, 3 of my 6 grandkids.
There's a possibility that I will be able to dive with a great-grandchild!
Alec
Happy new year Alec. I love your video's. You explain everything another way and give more information then at courses. I hope you can make these video's a long time
Thanks. I'm hoping to be able to do so.
There are lots of topics. I just have to keep up my energy and my interest.
Comments like yours helps with the latter.
Alec
Hey Alec! Thanks for all the great info! As I’m getting older,unfortunately, I’m looking into nitrox. My question,is it ok to use my Scubapro Mk 5 from the 1980’s with nitrox? Can I go back and forth from nitrox to air with the same reg? I remembered that when nitrox first came out I was told you needed a dedicated nitrox reg. What the right thing to do? Thanks a lot sir!
Any regulator that has been serviced in the last 10 years should have EAN compatible o-rings and lubs. Watch my video S10E02 Is Tank O2 Cleaning Necessary? It should answer your questions on tank and reg compatibility. Thanks Pete.
A.
@@AlecPeirceScuba_SeaHunter thank you Alec that’s the answer I was looking for!
Another great tip!!! Happy New Year Alec :D
Thanks God.
Alec
Nice video. A bunch of us took the Nitrox course thinking we could stay longer or deeper. After the course, we realize that wasn't gonna happen. Anyway, water under the bridge, but it's good to know that as we get older, we may have the option to use it, if we plan on more dives per day. Thanks.
Glad it was helpful!
I feel less tierd after 4 nitrox dives then 4 air dives in the same day
Apparently, that is one reason to use EANx. A diver feels less fatigued.
Alec
Another awesome vid !! I did pass my nitrox and I couldnt explain it better .... I find also that it helps in not getting as easily into hypoxia ...
Possibly.
Hypoxia should not be an issue for divers. It is usually the result of poorly maintained gear.
Alec
@@AlecPeirceScuba_SeaHunter true ... in my case though it was due to inexperience while in my open water and I had try to fin to much too fast to reach my buddy diver and then at the surface I had to remove my mask and reg and then snorkel also as nothing was giving me enough oxygen to recuperate ... I almost passed out ... I have learned then the importance of good shape and to stay calm and not rush in the water ;)
Happy New Year Alec!
Thanks Pierre and thanks for watching.
Alec
Great video Alec. I think Divers should know that nitrox is only safer if you do not dive your gas Ndl limits or you will have the same nitrogen gas loading as if you were diving air - More bottom time but the same gas loading.
Solid idea.
I use NITROX often if diving deeper than 50' I'm old and have quite a bit of scar tissue.
But I usually dive air tables when using NTROX. Double safety.
Alec
Hi Alex, incredible videos and I appreciate you sharing it all with us. I’m a fairly new diver and booked my first live aboard trip. Any pointers on what to bring on a live aboard trip.
Money! No. Just kidding. Other than tips and maybe alcohol, one benefit of a Live-Aboard is that everything is included.
I suggest that you have DAN Diver insurance, as much of your own gear as possible (at least mask, fins, snorkel, reg system and a computer) and a relaxed attitude. You are going to be spending a week in confined quarters with a group of strangers, some stranger than others. You need to be able to look away and not let things bother you.
relax, laugh and enjoy the diving.
Alec
Alec Peirce Scuba thanks Alec! I will keep all that in mind. I did just purchase all my own gear and plan on bringing it. Keep up the amazing videos. I’m getting my 14 yr old son certified in hopes of giving him a lifetime of adventure. He and I watch your videos. The history of things you teach help him understand the concepts of his class!
@@AlecPeirceScuba_SeaHunter JOHN3:16
I've just come back from a weeks liveaboard in the Red Sea (Egypt). A liveaboard is the perfect time to be diving nitrox. We couldn't have done the dives we did on air without exceeding our no deco limits.
I just got my Open Water Diver certification... and I got my Nitrox certification at the same time. I got to use Nitrox on the last of my Open Water course dives!
You will enjoy it a lot and if you ever think it does not make a difference in how you feel after a dive, use air once and see how tired you are. Welcome to the scuba world.
Alec, I'm surprised you didn't touch on how some divers report less fatigue post-dive because of the greater percentage of oxygen.
Next Nitrox video OK?
Take care.
Alec
@@AlecPeirceScuba_SeaHunter Cheers and thank you. Love your videos.
You get it wrong. Nitrox ist not about the higher amount of oxygen, but the reduced amount of nitrogen. Nitrogen is responsible for fatigue. Adding oxygen is just the cheapest way to get rid of it. Therefor many holliday locations offer "Nitrox for free" because, you get to dive more often.
@@Skunkiboi I can see what you mean with offgassing during deco but I can't rule out that being highly saturated in O2 has no positive physiological effects at atmospheric pressure. If you have a medical journal that covers the effects of Nitrogen gas on fatigue, I'd love to read it because I'm pretty sure my body would be infinitely happier getting O2 at the surface than something like heliox which would also displace the amount of nitrogen in the mixture.
It's there to displace nitrogen, yes, but I'd posit that it also has its own physiological effect-I'm glad to be shown otherwise.
@@YuriyDel There isn't one. There have been a couple of studies that were inconclusive. The "less fatigue" is a placebo effect that many believe works for them.
Once again Alec with a great video! But I would recommend talking about eanx and altitude
We will be doing more EANx videos. It's a vast topic with a lot of information and quite a bit of controversy too.
Thanks.
Alec
Alec, could you do a tec tips on full face masks. I'm in the process of getting cert and of course so much to choose from, been watching tons of your vids, any updated gear recommendations for absolute beginners, for those of us on a budget. Could you also explain the dive tables. Thanks for your hard work.
I can do a Full Face episode. I used to teach Full Face.
It's not a widely interesting topic.
Full Face is not common in recreational diving.
There are really only 2 suppliers and they are both excellent.
Take care.
Alec
mudman0572- if you're interested in FFM and safety, i recommend the Hollis MOD-1. i'm a recreational diver but i purchased a MOD-1 2 years ago. i absolutely love it (except for the limited Peripheral vision) and i bought it because of the safety factor. it's considered a "Double Half Mask" because it's possible to remove the "Pod" (2nd stage) from the mask without having to Doff the entire mask. so, in an Out of Gas situation, you simply detach the Pod and insert second 2nd stage to your mouth OR attach 2nd Pod to mask. (of course, if you have a Switch Block, you can switch gas on any FFM without Doffing mask but that's another story. i recommend this video ruclips.net/video/OuaQdQ56-iI/видео.html if you'd like to see the Hollis MOD-1 in use. (i actually talked with this guy before i bought mine. he's a very nice guy). good luck!
@@mattg3191 Thank you
Also a shorter surface interval between repetitive dives.
Possibly a benefit.
Take care.
Alec
Alec,
I recently went on a guided dive with a new diving club, and the tank they gave me had a standard Nitrox label on it. "Okay," I said, "I'm Nitrox certified. What percentage is this," since the tank was not labeled with eanx info. "No no, it's not Nitrox," they responded, "it's actually air."
We continued to discuss my surprise that they'd give me a Nitrox tank with regular air inside, especially considering the extra work they may have to do to recertify this tank as oxygen-capable now that it has been used to a lesser standard, as well as my discomfort that they didn't take the Nitrox label off and wondering about what other logical steps they may be skipping over... Ultimately, I asked to use their O2 analyzer to confirm it was @21%, and the dive master who had handed me this Nitrox-labeled tank swore up and down that he knew for sure that it was air and there was no need for me to test it. Finally, after considering the dive profile (
I own 6 tanks i keep 3 of them nitrox certified and the othe 3 for regular air. I ues all 6 with regular air. If i want to dive nitrox than i use my nitrox tanks. Common practices with my other dive buddies.
When you get a tank from a shop you can always ask them to analyze it in front of you. As a matter of fact a nitrox tank should be analyzed by the blender at the the of mix and then by the diver prior to diving.
"2. I decided never to rent an "actual" Nitrox tank from them, because I no longer trusted them to treat their Nitrox tanks with the additional caution they deserve. Does this seem like a good conclusion for me to draw?"
No, it's not a reasonable conclusion. Why would the tank being filled with regular air make you think they treated the tank any less carefully than if they filled it with Nitrox? I wouldn't accept ANY tank, Nitrox-labeled or not, from a shop that I thought might be filling my tank with oil-contaminated air, or in any other way using "less caution" when handling it. Regular air is, practically speaking, just EAN21 Nitrox if you think about it.
Another excellent video, Thanks! I’m still waiting for the one on Full Face Masks. Can’t wait to hear you take on them!
Thanks.
Alec
Just a point or two - in EANx the x stands for the fraction of oxygen in the mix. You may see it written out as EAN32 for a 32% O2 nitrox blend.
While we often call it Oxygen Enriched Air, the added oxygen is not the primary benefit, but it the gas used to displace the nitrogen, the inert gas, in the mix. The N2 is the limiting factor from a decompression viewpoint. The body does not absorb O2, it metabolizes it, which is why it does not have a negative impact on your dive time.
Fat tissue is considered a slow tissue in the body, it has less circulation than muscle and absorbs inert gas slower. It also off gasses slower.
All good points Jeff. Hope everyone reads this to pick up some points. Thanks for watching.
yes, nitrox is usually made to allow longer dives but you may reach the O2 toxicity limit faster than narcosis with air
and tech dives its used for deco stops to reduce time
Thats true too. Thanks for watching.
When we go to a place like Bonaire or Roatan we always use Nitrox. We like to get in a least 4 dives per day and usually 5 during the week. As some people pointed out, we found we had less fatigue at the end of the day than when we used air. Although, Nitrox limits your depth there is rarely a need to go below 70 ft to see most things. If using a decent surface interval we found there no issue with either nitrogen build up or oxygen toxicity after the 5 dives. Most places in Bonaire will give you Nitrox or air for the same price so the Nitrox certification is definitely worth it.
I love EAN diving, I'm not as tired and in my old age that's a good thing.
Hey, where in Roatan did you dive? I'm a native of Roatan. I'm glad that you know our island, greetings to you 🖐
@@fredyg.1561 We were mainly around the west end. I have a RUclips channel, Virusking, where I list each Roatan dive site along with a video of our dive. We also did the shark dive on the other side of the island. I think we got 21 dives in that week.
I almost booked bonaire but I'm unwilling to live with some bs covid restrictions. Opted for Quintana roo
@@fredyg.1561 we were at Anse Chastanet in June - fantastic, and dove nitrox the whole time.
Do you need to be an advanced diver for nitrox? Or as an open water diver you can take the course?
The Enriched Air Nitrox course is one of PADI's most popular and you can take it anytime.
In fact, since it is an academic-only course, no pool or open water, you can take it before you are certified and then become certified during your open water divers.
Have fun.
Alec
@@AlecPeirceScuba_SeaHunter ok nice! Thanks! Love all your videos! One of the best scuba channels on RUclips in in my opinion!
I'm confused. I thought nitrox extended the no-decompression time limit, extending bottom time...
Recalling from my recent PADI Nitrox course training, I think you're partly right as that's the net effect of reducing Nitrogen on-gassing... however Alec hints at the major concern which is Oxygen toxicity.... both immediately because of depth (partial pressure of Oxygen exceeds safe levels), and accumulation/build-up over time, leading to Central Nervous System poisoning...hence the possibly shortened later dives. It's a balancing act as always.. no silver bullet.
I think it's a semantic argument. If you hit your NDL before your turn pressure then nitrox extends your NDL and therefore your bottom time. If you're like me and breathe down your tank well before your NDL, it won't help because your breathing rate stays the same so you'll still run out of gas before NDL. Similarly if you were planning a dive to a certain depth on air, but the NDL was too short to make it worth your while, **as long as you don't violate the MOD of the mix**, you'd get more time at that depth which might put it into the realm of "ok it's worth my while now".
Sean Walberg You may want to learn sidemounting since it doubles your gas supply (as well as other benefits).
Yggdrasil42 Why use a side mount? You can use Doubles, twin 72s, twin 80s, twin 85s, twin 100s, and get better performance than with side mounts. And as for cost, side mount diving costs just as much as doubles :)
Jason Wheeler You're right, but Oxygen Toxicity takes quite a while to build up. Even on days with 3 or 4 dives (like on a liveaboard) you won't run into it. So the extended bottom times far outweigh that downside.
Is it a mix of nitrogen and oxygen to decrease the risk from deep dives. Or am I missing something.
EAN reduced the amount of nitrogen in a divers system to allow longer dives but causes a reduced depth. It's a trade off but EAN also makes a diver feel less tired from less nitrogen. The Enriched Air course explains everything you need to know.
A
Alec, is it true that using the Nitrox I can consump less gase mixture? Because every breath that I take has more ppo2? Is there any studies about how we metabolate oxigen in the different gase mixtures with different partial pressure of gases? Great video, Alec.
That may seem sensible but it's definitely not the case.
When you inhale, the same amount of air by volume enters your body on every breath, limited by your lung capacity.
Then your body consumes oxygen as required by your body functions. If you are cold or working hard, your body requires more oxygen so 2 things happen - you breath more rapidly (more volume) and your body consumes more oxygen. Interestingly, the amount of oxygen that is used from each breath doesn't vary much. The body gets most of its required extra air from the increased rate of breathing (more volume). This can be shown by working had on a 20% mix and noting the increased breathing required to meet oxygen demands and then comparing that with working hard on a 32% mix. In both cases, you need to breathe faster to meet demands and the increased rate is similar. Having a higher oxygen percentage does not allow the body to not breathe faster to meet demand.
So whether you are breathing a 20% mix or a 32% mix, the body only requires a fixed amount of oxygen to function and that's all it uses from that breath. If you were breathing pure oxygen (100%), only a small fixed amount of that oxygen would be used on each breath. The principle of rebreathers confirms this and that physiological process is the same regardless of the PP.
Partial Pressure is not related to a bodily function. It has nothing to do with the respiratory function. It is a physical or physics function and only affects the rate that the gas is dissolved in the blood. Dissolved gas, nitrogen, oxygen or otherwise, as in decompression sickness, is not used for respiration.
Bear in mind as well that the body does not respond to oxygen. Your body does not know (nor care) how much oxygen is in the breathing mixture. It responds to increasing carbon dioxide from the respiratory process. You have no idea what the oxygen level in a breath is. You only know when you have used as much as required and you only know that because of the increased level of carbon dioxide.
Also realize that the benefit from the use of EANx is NOT from the increased oxygen but from the decreased nitrogen. Using EANx increases diving safety by lowering the risk of decompression sickness.
This is a non-scientific explanation of the respiratory process. There are many factors involved in the process. However, it's a pretty accurate and clear explanation of how it all works.
I hope that helps.
Alec
@@AlecPeirceScuba_SeaHunter Alec, you know, I'm really have heard from several divemasters like Nitrox has the advantage in term of gaze consumption. I was doubt. I will show them your post. Thank for clarification))
Air consumption will be the same. This has actually nothing to do with the amount of oxygen in your body or the partial pressure of it. But the amount of CO2 that's build-up in your body. This triggers your breathing.
@@AlecPeirceScuba_SeaHunter so you can't hold you breath longer breathing say pure O2 because of the CO2 build up ? how do freedivers who pack their stomach with air do it then ?
seems sensible that Nitrox higher oxygen would allow you stretch your air longer if you hold it (which I know you're not supposed to while diving but that's really because of depth changes).
@@alaind831 Free divers take deep breaths before diving to expel as much CO2 as possible. That way their brain doesn't feel the starvation for air, allowing them to stay down longer on one breath.
How long does it take Nitrox to fully "mix" after a fill?
1 second. There is no mix time for nitrox as its fully mixed when ready for diving. Watch S08E21 Now Is Nitrox Made? and S11E19 Scuba Myths: Tank Air Goes Bad. These two will answer your questions ND.
@@AlecPeirceScuba_SeaHunter thank you Alec!
Alex, while I’m not sure there’s science behind it, you did not mention that many people feel Nitrox equals less fatigue after diving. Whether it is a placebo or not I feel better after Nitrox dives. Your thoughts? Thx
D H There's some science behind it. A) An increased oxygen level in your tissue means that less energy will have to be spent to do the same amount of work B) Less nitrogen in your tissue
D H there is less nitrogen in the mix available for uptake during the dive and subsequently less nitrogen to eliminate post dive which more likely results in a feeling of less fatigue post diving versus an energy boost from a higher oxygen levels relative to air
DAN has studied and proven that there is no proof that Nitrox reduces tiredness. Nitrox can actually increase oxydative stress. www.alertdiver.com/?articleNo=1836
See some other comments about that DH.
Thanks.
Alec
th4n Great article. Thank you.
If I have a tank that has been cleaned, prepped and labeled for nitrox, and want to fill it with regular air, will the tank and valve have to be cleaned again to go back to a nitrox blend?
Yes, UNLESS it has been filled with "clean air." That would be air that has been through a system cleaned just like your tanks.
Don, how do I know if the fill facility fills with "clean air"? Wouldn't/shouldn't all reputable dive stores/facilities fill a tank with clean air?
@@rickkinney2544 If they offer nitrox, they'll be pumping extra clean air. The majority of places will be delivering this, just check when you give them your tank for filling
Yes but you can always go EANx 21. It's still Nitrox but at the same blend as surface air-assuming you'd do this because you were doing a deep dive and needed the MOD thereof. That's if you want to avoid having to get everything cleaned again.
If your dive store has EANx, it will also have OCA.
OCA is Oxygen Compatible Air - simply air that is certified to be clean for Nitrox use. It is the air that they use to make their Nitrox blends.
If you use OCA in your Nitrox tank, it does NOT have to be cleaned for future Nitrox use.
Ordinary breathing air may not be suitable for Nitrox use.
Some stores charge extra for OCA. Good stores do not. While there may be a slight additional cost to the store for making OCA, they have to have there anyway, whether you buy it or not. That extra cost is covered by the Nitrox users.
Take care.
Alec
Is it the high body fat and low skeletal muscle (often happens with age) that causes it?
What if one is old but not fat with high percentage of skeletal muscle? (eg 50% muscle - old but lean and muscular)
Alec, you are da man! Thanks for the videos! 💪🏽😎
Thanks Joe.
Alec
Hi Alec! Can i fill my normal steel tank with nitrox ?
Any steel scuba tank will a current VIS and hydro should safely fill up to 40% enriched air without special cleaning or o-rings. Take care Marian.
Hi Alec
Can you tell me how to calculate the amount of exposure to oxygen from multi-depth dives
As the tables are based on the fixed depth according to the values of exposure
And the second question does it appear in the Maris Smart Air computer? the % of exposure ?
The third question: i know that nitrogen absorbs less than oxygen in diving usually. If that is the case, does oxygen have the same property, or is it that when it reaches the upper limit of 1.4, we can only go up to a higher levels and drop quickly? I hope the question is correct
If you think it is appropriate to explain it in a video, I would be grateful
As our trainer died, he made a technical dive at 65 meters, then after he finished the dive after 20 minutes and at a depth of 35 meters, he wanted to change to the Nitrox 37 cylinder, so he mistakenly replaced it to the cylinder with a concentration of 80, where according to the words of those who were with him, the oxygen was almost at His ascent reached 1.6. When the error occurred, the ratio shifted to 3.55. Can you explain what happened?
Thank you for your wonderful communication.
From your description I understand the consequences of the O2 partial pressure of 3.55. Way to complicated to explain and I don't want to share partial info that others may use incorrectly. Best thing is to post a question to the tech experts on www.scubaboard.com. You will get lots of info on this incident and explanations/links and help on the question of multi-depth diving. Hope this helps and safe diving.
Alec, first of all thank you for your videos. My question today is that I've been watching different dive configurations, and I see some parts in Europe use a 7' primary, and then they have there back-up on a bungee around there neck. I would just like your opinion on the matter because it seems to me that the primary should never leave my mouth. Just wondering why they choose that way.
The person who is out of air needs a working reg immediately. You know the one in your mouth is working, so that is what you should donate. Seven feet allows the divers to swim comfortably side by side or inline while sharing air. Having your backup under your chin ensures it will not be dragged in the mud, you can get to it quickly and if it ever leaked, you would know it right away. It's a much safer way to dive than having a 40" hose between two divers or trying to breathe from a second stage that also works as a BC inflator which needs to be free to operate during an ascent.
Pacificcoast has provided an explanation for the use of the Hogarthian regulator set-up (named after the guy who promoted it).
I personally am NOT a fan. I see no reason for it. The standard set-up (so-called because it works well for 90% of all divers) is as close to perfect as you will find for diving and for handling emergencies. Changing things drastically is not good.
Having said that, there is an application of the 'long hose' set-up that could be valuable. It is in fact, the impetus for its development but pacificcoast either didn't know that or missed it. If a diver and his buddy are in a cave or other confined environment where a diver may not be able to reach the normal octopus, the long hose may be useful because it can be passed back through the legs or down the side of the diver to the diver in trouble.
Several of pacificcoast's comments are simply not based on fact or experience.
1. no diver would enter the water if he wasn't sure his entire set-up was working, maybe especially the octopus
2. 7' is much too long. 3-4' is good. You need to be able to reach the diver but not so close as to have him interfering with you. At
7' you can't reach him and you have a lot of twisting hose to contend with. Not fun.
3. he's right that you know the one in your mouth works, but if you're not so sure about the other one - why would you give it
away?
4. the octo should be attached right in the middle of your chest. It won't be dragging in the mud and is instantly available by
either diver
I have discussed this issue in several other videos as well as the question about BCD-mounted safe seconds (which, like pacificcoast, I also don't like).
I hope this answers some questions. You can find lots of information (too much) about the Hogarthian set-up online.
Take care.
Alec
thank you@@AlecPeirceScuba_SeaHunter
I dive in this configuration. (located in Ontario) it all comes down to preference. I have had to share in low air situations before and i kinda like that who i'm handing off to isn't right in my space to complete the dive. the extra length gives a buffer zone. this does not mean that you wouldn't still link up while you are sharing. just means that if there is a little drift apart for some reason the Reg isnt yanked from their mouth.
The reason you can't go deeper with nitrox is oxygen toxicity. The higher percentage of oxygen in your tank means lower maximum operating depth(mod). A 21% of oxygen tank has a MOD of 187 ft. while a 32% has a MOD of 111 ft.
Correct. I plan to elaborate on the disadvantages of Nitrox in a future video.
EANx (Nitrox) can be very beneficial but it's not the panacea or cure-all as some divers think.
Alec
Alec Peirce Scuba Thank you. Could you mention whether if nitrox helps with less fatigue post dive?
It all deals with the increased ppo2 %. Recreational divers can go up to 1.60 ppo2 on nitrox 32. Also it's more then just ppo2 it's also a time that your breathing that ppo2. Took my nitrox class got my nitrox endorsement. I recommend nitrox class for any diver. Way more to it then I'm typing but check it out. You'll learn alot
Enlightening,Thanks.
Thanks for watching.
Alec
When I first went and got certified for Nitrox (over 20 years ago) my diving buddies and local shop said I was going to kill myself with that stuff.
After they actually researched and learned about it, it didn’t take them long to change their mind.
A typical early experience with the dreaded 'Voo Doo Gas' as Skin Diver Magazine first called it. Today EAN is second to u/w photography in new certifications. Even divers can adapt to new ideas sometimes.
this was a little misleading. Nitrox certainly does help you stay longer if you are doing repetitive dives and don't want to have deco dives (what most rec divers do). As matter of fact if you do 2+ days boat dive trips and/or 6+ dives a day it might be the only way to not sit a dive out and have very long surface intervals... sure it's not giving you more air so you can still run out regardless.
Diving EANx allows faster off gassing during surface intervals as the nitrogen load is less in the different tissue compartments. So you are correct but Alec was referring to diving a dive at a time and how with certain mixes, you can actually have less time; example EANx 38% and deeper depth (>100 ft or 33 m) and your dive time will be limited compare with air.
@@rgorji even a single dive at common rec depth of 60ft (I'm not talking about depth where Oxygen poison is an issue as Alec target audience are rec divers), 32% nitrox will let you stays longer than air without having to deco - people might run out before that, but you can have a longer no-deco dive time. at 100ft, it's significantly more (like 50% more no-deco time).
Also missing listed benefit of Nitrox is that some feel less tired after dives (less nitrogen in body).
Alain Dumesny You are correct.
Don't fight boys. You're both right.
This is the first of a couple of EANx-related episodes.
I wanted to dispel some misconceptions about the use of Nitrox, primarily that it allows a diver to ignore dive tables and stay down as long and deep as he likes. Yes. There are divers who have been told this and who believe it. There are many instances where, even on a single dive, benefits arise from the use of Nitrox.
I have answered some questions about the 'less fatigued' issue Alain. It's not yet been defined as a proven medical benefit. But, as I've said, if you feel less fatigued after a dive using Nitrox, good.
Thanks for watching guys.
Alec
@@AlecPeirceScuba_SeaHunter yes but in your video you could have said "Nitrox, with it's most common 32% mix, will allow you to have longer no-deco times and shorter surface intervals as there is less nitrogen for your body to absorb, but will limit how deep you go as oxygen becomes toxic at depth". Since you skipped the more technical aspect....You only focused on deco sickness - which is important, but indirectly implied if you no-deco times are longer but you still dive shorter dives, there is a larger margin of safety. Someone watching this video might just skip learning more about nitrox (unless old/overweight).
I was on Bonaire a few years ago and I noticed all american divers where using nitrox and dutchies did not. Nitrox isn't that popular here in Netherlands , I also do prefer normal gas to keep things simple and I can use any fill station I want. We even do have unmanned self filling stations for normal gas over here in Zeeland, Netherlands.
Nitrox is a bit of a fad over here. Many divers use Nitrox because their buddy does, or it looks cool, or they think it makes them better divers - none of which is right!
For most divers and most dives, normal air is perfect.
I tried to set up a 24 Hour Fill-It-Yourself air station at my store but didn't get it completed before I retired.
In the US (I'm in Canada), I'm sure it would be impossible for liability reasons. The first diver to hurt himself or get a short fill would sue the dive store and it's over!
Take care.
Alec
@@AlecPeirceScuba_SeaHunter I want my buddy to use the same mix as I am, so we have the similar no stop times, and/or decompression profiles.
Personally I find the most benefit with nitrox and square profiles below 70ft. A multi-level profile, like a Cozumel wall dive, has enough things to see at shallower depths that you typically don't need nitrox unless you are doing more than 4 dives a day.
I do know of one self service fill station in the States, of course it is in cave country so I am not sure if it is because they march to the beat of their own drum or simply that there is no demand.
I 💛 Nitrox!
Ahhh! Crazy gas. Love it!!!
Take care.
Alec
Being 66 years old I wonder why dive computers or tables do not have an age factor.
Tables do not but dive computers have a 'conservative' factor to compensate for a lot of issues: age, health, married! Using a more conservative setting changes the algorithm to reduce dive time and other factors for a safer dive is your not in Navy Seal condition (that's me). Every modern computer has this so reading any dive computer manual will give a detailed explanation. Take care Danny.
@@AlecPeirceScuba_SeaHunter Very good thank you for the reply. I have a Sherwood computer on order but have yet to download the manual if it is available online.
Good point running machines have age and weight so why not dive computers
You're the best!
That's what my grandkids say John.
My wife too sometimes, depending on her mood.
Take care.
Alec
@@AlecPeirceScuba_SeaHunter Funnier words have never been said. Safe diving!
Variations in which gases do what are the premise of nitrox, I was lead to believe that if you used Nitrox then since you inhale less nitrogen, your decompression rate for your depth would be longer - enabling a longer bottom time - but since oxygen is toxic enough to kill you below 8 meters at 100% (trivia from an old rebreather documentary I haven't had debunked yet) your depth limit - or the depth at which you should under no circumstance should you exceed - is shallower.
I knew a guy that dived with Nitrox in Thailand and he did have a fair bit of body fat (and had a stint in a decompression chamber) so I guess that confirms that hypothesis!
The result is that if you use enriched air - you can stay at your maximum depth with less worry of DCS and fatigue, but more risk of oxygen toxicity - which is different from nitrogen narcosis only in that it doesn't get you drunk but rather floods your nervous system and risks a more fatal reaction (seizures, blindness, sudden lack of awareness and death) instead of getting you a little giddy and forgetful. It's still a form of gas narcosis, it's just that your risks change form and there are different calculations you use to calculate your decompression stops (many newer dive computers have adjustable nitrox settings) but of course, just watching your bottom time is not enough to keep you from running out of air! A breath is a breath and at whatever depth and the same starting pressure, good breathing control is the only way to prolong a dive!
(Also, between you and me, I don't mind the fatigue too much, it makes for a great night's sleep!)
Oxygen toxicity doesn't become an issue until the PP (partial Pressure) of the oxygen reaches 2 atmos (approx 30 psi).
Using normal air (20% oxygen) that wouldn't occur until the diver gets to over 300' - not likely to occur. At 300', oxygen toxicity is the least of his worries!
Using an EANx mix of 32%, oxygen toxicity doesn't pose a problem until he reaches 200'. Again, not the real concern.
So, oxygen toxicity is not a reason to avoid the use of Nitrox. It is addressed in Nitrox tables and with the use of a computer anyway.
Most modern dive computers have Nitrox setting. You simply enter your mix and the computer takes over.
It's true that I always sleep well after a good day of diving, crazy gas or not!
Take care.
Alec
Oxygen Toxicity is a function of partial pressure, and time. As noted by Alec, you doesn't become instantly fatal until you are at a PPO2 of 2. At every other PPO2 there is a time component from 45 minutes at 1.6 to 720 minutes at 0.6 (per the NOAA Diving Manual). There are long term exposure limits, but those aren't that relevant unless you are a commercial or scientific diver.
As far as narcosis, Oxygen is more narcotic than nitrogen, that is why narcosis is never mentioned as a benefit of Nitrox, if you want to reduce narcosis once you get below 100ft/30m, it is time for Trimix (which incidentally is why some DIR agencies require Trimix below 100ft).
You are right for many cases air time is the limit of their diving, for me I have reasonable SAC rate for my age, and sex, so for deep dives I am more often limited by my no stop time. EAN32 at 100ft I get 30 minutes vs 20 minutes for air (per the PADI RDPs). So for $2.50 more I get 50% more bottom time. And my computer handles all the no stop times, and the decompression profile if I stay long enough incur a mandatory decompression stop. And if my primary computer breaks, my secondary computer does all the same too.
Well I guess Alec is right, there is allot to learn about alternative air mixes and they all mean different styles of diving - I guess that's why technical diving is so much of a standard of its own!
@@Teampegleg > EAN32 at 100ft I get 30 minutes vs 20 minutes for air (per the PADI RDPs). So for $2.50 more I get 50% more bottom time.
which is why I mentioned Alec video is misleading as most rec divers will get more non deco bottom time with Nitrox (if air time ins't the limit already). I too often get limited by no-deco, not running out of air, especially repetitive dives... Maybe my cobra is too conservative, but I'm also not as young now.
Alec: > Using an EANx mix of 32%, oxygen toxicity doesn't pose a problem until he reaches 200'. Again, not the real concern.
My Suunto cobra with default 1.4 gives me 114ft at 32% if I recall (I can choose up to 1.6 to increase that depth) which is quite a lot less than 200' you mentioned (at 2.0x ?)
@@alaind831 The Cobra is pretty conservative particularly on repetitive dives, as the bubble model doesn't like repetitive dives. A dive computer that uses a pure dissolved gas based model, like the Buhlmann models, might give you a bit more no stop time on repetitive dives.
Alec, really enjoy all of your videos, keep up the great work! I have only been diving since March of 1974, so I am certainly a neophyte compared to you. Certified in 2007 in EANx, my instructor and I had many conversations about potential oxygen toxicity and its scary, sometimes lethal effects. O how I do love Nitrox, because just one of its benefits for me, is that most the time I feel better and more refreshed after each dive. For my shore diving I exclusively use 40%. It gives me an MOD of 82'. As the years roll on however, I become more, and more concerned and literally afraid of oxygen toxicity. Because according to my instructor, once O2 toxicty happens, most of the time a person goes into convulsions. I am a health care provider, so I do know the anatomy of the body quite well. And once one loses control of the diaphragm, death quickly ensues. My 2 questions to you are how best to eschew the pernicious state of oxygen toxicity, and once one is unfortunately in that situation, what is the best remedy for it?
Anxiously looking forward to your reply........
When nitrox first was introduced to diving many called it 'Voo-Doo' gas. They had the same prejudices against it as single hosed did to the established double hose crowd (we know who won that). Today EAN is almost the same as u/w photography as the most popular specialty to get. Thanks for the history lesson from another 'stone age' diver.
Cons: more expensive, higher risk of fire/explosion on regulator first stage and be ready to accept a shorter maintenance interval on your reg. If your buddy not using nitrox will end the dive sooner.
Possibly but in 50 years in the dive business, never had an explosion in my shop or any nearby. The last point is probably the most common problem but getting EAN certified is easy so get your buddy on board.
A
@@AlecPeirceScuba_SeaHunter , Pros: im using nitrox for a long time already, that means when i reach my 70s wont have that DCS issue 😄👍
I think oxygen toxic is a scary thing!! because once it did happened ,you probably don't even know and it doesn't matter what in the book said...because when you are diving ..there are so many things to distract you more than just notice on yourself (and how your body feel ). I am a Nitrox certificate diver, but honestly... until now I still can not find a very good reason to keep using Nitrox , Nitrox cost more money , can't go too deep too long time , everything depend on dive computer, awful chance to get hit by Oxygen toxic. Extend diving time to stay longer underwater is not match to the fact (in my case) that we dived always with a guide and group, there for meaning of we come up all at the same time. ...not to mention about ...shorter surface interval time... :( because we all diving as a group which is not everyone prefer to pay and using Nitrox . Thanks Alec to point out this Nitrox topic.. Love your video as always.
Several gas-related issues that can affect a diver are not obvious.
If you choke on some food, that's obvious. If the oxygen in your air is too low or too high, you will pass out - and not even know why or that it's happening.
This is one of the problems with Nitrogen Narcosis where the most common feeling is that 'everything's OK' - as you pass out.
And Decompression Sickness - you don't feel anything, until it's too late.
Or Carbon Dioxide poisoning (common in diving) which just makes you breath faster and faster as you pass out.
Gosh, I'm talking myself out of scuba diving!!
Nope. All these problems are easily avoided.
Nitrox can be useful but it too must be used properly.
Take care.
Alec
If you're always diving with a group and a guide (I suspect as you become more experienced this won't be the case but that's a different argument) and therefore you have the same dive profile and surface interval as divers on air, then using nitrox will increase your safety margin for DCI, you only need to make sure that the max depth isn't greater than the nitrox mixes MOD, very easy to calculate and not dependant on a computer.
I love EANx. I feel much better after 2 or 3 dives with Nitox than when I dive with air.
Even with a lighter wallet???
Kidding. If you feel better then NITROX is right for you.
Take care.
Alec
Agree...he didn't really explain the benefits very well. When I'm doing 3-4 dives a day on a 7-10 day dive trip or liveaboard, I'm diving Nitrox all day because it makes me much less tired.
Now we just need the industry to embrace helium for recreational divers, enabling divers to manage/eliminate narcosis all the way to 40m and beyond.
Heliox is very common in Southern California. Though it seems like rebreathers are overtaking it in popularity.
@@LarsSveen Are you sure you dont mean helitrox(limited trimix)? As true 21/79 heliox is pretty rare anywhere ive seen, including SoCal. Also, rebreathers make sense with the cost of helium once you start using more of it, im on an optima myself.
@@Mrich775 Sorry, you're right. I meant Trimix.
@@LarsSveen I figured, trimix is definitely common just really reserved for tech divers currently except for a few programs in IANTD, and I see the reason more as the same fear of voodoo gas just directed towards helium than any real concern. Even in recreational NDL dives a little helium really clears the head at 35-40m and has little risk given basic training. It should be more commonly used and accepted within recreational (non-technical) diving I think.
@@Mrich775 I know there's at least one shop down here that really pushes people to get helitrox cert. PADI now even has tech diver courses, though I'm not sure if trimix is part of that. So it seems like it's getting easier to become a rec tech diver, and get some helium blend.
As usual, it is an excellent video with an excellent explication of the product.
To me I fear those mix for an obvious reason, the human body is designed to run on a gas mixture of about 20% oxygen, when you modify this mixture, nothing says that it will not cause an irreversible damage to the lungs or elsewhere in your body.
As you say so well, when we become old, the sensivity to feel narcosis and develop bends is increased by an important factor BUT, as we gain age, we develop some wisdom that avoid going in trouble.
As amateur diver, I prefer to stay on the safe side and to not use these mixtures even my dives are shorter.
Human body knows nothing about O2 PERCENTAGE but partial pressure. For long exposure PPO2 should be between 0.16 and 0.5 bar. For shorter exposures the upper limit should not normally exceed 1.6 bar. If you are wortied about elevated PPO2 you should not dive. If you dive to 100 ft/30m i.e. 4 bar with air the PPO2 will be 0.84 bar. If you dive with EAN32 to 50ft/15m the PPO2 is 0.8 bar. From your lungs point of view the load of the air dive is slightly higher.
Without getting into the detailed physiology of EANx, I agree with you.
Increased O2 is not a danger to the body - to a point. And every body is slightly different. There is no magic formula.
Long and detailed studies have shown that EANX gives the older diver an increased safety factor.
Hopefully, that 'older' diver also has the wisdom to not let that increased safety factor affect his dive profiles so that it is lost.
It's a bit like getting a 4 wheel drive vehicle.
You see it all the time. Someone buys a 4 wheel drive vehicle and they start to drive like a maniac! They don't stop to realize that they have always had 4 wheel brakes! The drive may give them more traction on acceleration and a bit more on cornering but it doesn't help with braking at all. They can't stop any quicker. So they think they can go faster with 4 wheel drive and they do so. Now their required braking distance is increased but not their stopping ability.
That's what I mean by acquiring an increased safety margin and then frittering it away!
Take care.
Alec
There is one more (relative) plus to having nitrox available.
If there is an incident you can give the victim your nitrox bottle to breath from.
32% Beats 21% when there is no 100% around.
That's true. It's a fact that enriched air, preferably pure oxygen, is good in treating a diving accident.
Alec
I just learned this in my PADI rescue diver course :p
isn't oxygen toxic if you go too deep
Yes it is, and that's why there are special dive tables and dive computer algorithms for use with Nitrox. One of the tables is a "MOD Table," [ Edit: See www.deep-six.com/nitrox/eandepthtable.jpg ] where your maximum operating depth is listed based on the percentage of oxygen. For example, when I'm using EAN36 (36% oxygen), the deepest I can dive is 95 feet. The good news is that for any allowed depth, my allowed bottom time without needing decompression is longer than with standard air, because there is less nitrogen uptake.
This is one of things covered in suitable certification.
Perfect Brian.
This is the area whereby divers get the impression that they can stay down longer on Nitrox.
In specific circumstances that may be the case but that is NOT the reason nor the benefit to the use of Nitrox.
It is purely a safety issue.
Alec
@@AlecPeirceScuba_SeaHunter really confused about your statement above... no-deco times are longer on nitrox (using rec depth limit table listed above) and shorter surface interval - reason why many of us use Nitrox, if air supply isn't your limit, for square profiles.
Now I know why they call it "Geezer gas"
Because it's so good.
Well now that I’m old and fat maybe I will waste money on it. Thank you my problem is I did commercial diving for years and not sure what the class gains me. I’ve done a lot and the dive computers are amazing(tables would limit me). I just don’t see the whys with 80 tanks I can do four tank dives which is enough(day). I don’t get in to trouble with any algorithms(most dives less than 60 ft). Diving deep I would never use Nitrox period. O2 makes me hiccup then hearing and then mental issues if I’m breathing pure o2 for extended times(chamber) deeper than navy recommendations. Just saying I think it’s a lot of marketing. I’ve been lucky over the years and never gotten sick following navy dive tables or modern computers. But thinking as I get older on shallow dives it might be best to switch to Nitrox. Thank you
Some might consider me old at 75 but I don't. Still lots of diving left in me and Nitrox is very good for these old bodies to minimize our nitrogen loads. Keep on diving which ever way you're comfortable William. Don't quit, but adjust your gear and air to our mature age! Thanks for watching.
A.
Alex actually you can dive deeper for longer on Nitrox, eg multiple deep dives in one day, my first dive was 43m @ 26% I could not have completed the 2 x dives at that same depth for the same amount of bottom time on Air with out going into Deco. I know you have probably tried to simplify it but statement is correct with an explanation. 😉
Of course, there are dive profiles using Nitrox that may have extended times and depths.
My problem is with divers who get Nitrox BECAUSE they think they can dive deeper and longer.
They may not even know what they're doing.
That's the problem.
Take care and thanks for watching.
Alec
Mark at 43M nitrox is really not suitable or you have just a 26% mix which will only give EAD of 40M and a 9 min no-deco time. Below 40M only trimix is suitable.
Carlo Kop that’s what I said and that’s what I did. Nitrox is suitable for this dive profile and is a better option than air. 🤦🏽♂️
@@forgot_my_name_again when you're talking about dives to 43m and / or utilising trimix then the no deco limits become redundant IMO.
@@clarkeysam that is true. But take narcose and gas consumption also into account. You will most likely use 21 to 35% helium that will decrease no-deco a bit. But unless it's a bounce dive or dive with doubles or stages you only have enough gas with you to get 7 or 8 minutes of bottom time before you reach the point (+/- 130 bars with a single 12liter tank at 43M) where you do not have enough gas to do a emergency assent when donating gas.
The truth is, I can go deeper and longer.... at the buffet. No Nitrox needed as I do not have time to breath at a buffet.
Just don't get in front of Kevin, he will run you over...
A
@@AlecPeirceScuba_SeaHunter I'm far too round to be run over! 😂😂
He isn't a killer, he is just a man with a tank
A big tank too.
Many cautious divers use Nitrox, BUT still dive std air settings on their computers. Great built in safety buffer.
It give an additional safety factor but they must remember not to exceed the maximum operating depth on EAN.
@@AlecPeirceScuba_SeaHunter This seems dangerous to me for the reason you stated...the main hazard factor diving Nitrox is the lower MOD vs. a standard air mixture and the diver has to always keep this in mind as the computer would be showing erroneous information. I guess one workaround would be to set a depth alarm for the appropriate Nitrox mixture being used.
😄 Well I thought Nitrox taste like nitro (nitrolycerin) and this is the reason why the name comes from. 😆
Oh no. Just more nitrogen, no smell at all, than regular air.
A.
@@AlecPeirceScuba_SeaHunterI know, it was a joke, because that would explain why it's more expensive. 😜