Should you be using Trimix instead of Nitrox? - Dive Pros Roundtable Ep.2
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- Опубликовано: 4 июн 2024
- Steve and Nick are back to discuss the role of Nitrox in recreational diving, and also why some Nitrox instructors are putting their students in danger.
Thanks for the shout out Gus :-) I guess I beat you at your own game 🤣, off course Nitrox is not total BS, but It just has a very narrow range where is has a benefit. But I got you guys talking !!
We don't like diving deeper than 100ft or 30m on any mixture containing N2 and O2, mostly because of gas density. Shallower than 70ft or 21m, there are no real time benefits, because gas quantity most likely becomes the limiting factor. So between 70ft and 100ft sure it makes sense. As well as on multi day trips with multiple dives per day in this range, it makes sense.
If anyone is interested in the podcast episode the boys are talking about, you can find the UTD Scubadiving podcast on your favorite podcast platform. The latest episode is quite controversial also , 😉 its about equipment and, I explain that its not equipment that does not kill you but choices do...
You should get Simon Mitchell and David Doulette to come on and talk about helium penalty.
As a CCR diver (of course in Sidemount 😊) I absolutely disagree with the idea that Nitrox is useless. Why should I waste expensive Helium in the depths less than 35-40m (115-140 feet) when I have a mobile Nitrox mixer (rebreather) with me. Even if diving open circuit I would choose a NX30 for a 35m (115 feet) dive instead of a TX mix, just to have more bottom time or reduce decompression obligation and probably use a stage bottle with NX80 or pure O2 for the better decompression. For deeper dives than 40m (no difference if CCR or OC) I definitely go for a Trimix.
Nitrox for accelerating deco stops is invaluable.
Nitrox has another benefit besides extending your NDL at a certain depth for rec diving and that's being able to do multiple dives in one day with a shorter SI in-between due to the less amount of nitrogen you absorb from the nitrox mix compared to r3gular air. Nitrox still falls within the category of recreational diving because once you start going below 30m you are risking CNS oxygen toxicity with your pp02 going up on Nitrox (depending on the blend of course). Of course you are still beholden to your SAC rate so you may only buy a few more additional seconds of BT before you head back up but the true benefit imo is in doing multiple dives.
Nitrox and Heliox are tools for specific purposes. But He is a limited, finite resource and so very expensive; that's the gas you shouldn't be wasting. Oxygen is relatively cheap and sustainable. I believe if you don't truly need trimix you should be using nitrox.
Tell that to the GUE elitists
I like this format of discussion.
A topic I'd be interested in hearing is how to sus out a good instructor. I think we've all just dropped into a class and taken what we got. Only to find another instructor later that was epic, and you wish you could've started with the second instructor.
Don’t know how this got in my feed but quite interesting!
Absolutely love this series and the panelists. Hope to see more of this format in the future!!
What Nitrox gives you on a 20 meter dive is a shorter surface interval between dives.
Not to mention is does keep you safer overall, it reduces your risk of DCI, which everyone knows can happen to anyone, at any time, at any depth. Saying Nitrox is useless is just a garbage statement
In the Pacific North West (Vancouver Island BC) I dive 35% nitrox a lot as most of our shore dives max out at 100feet. We often do 90+ minute dives with out deco just following the shore profile back. I dive sidemount but my dive buddy is diving single tank (Steel 120). We also often dive shallower dives and use nitrox on these dives as well. When I am teaching I tell my students. Once you are coming up from a dive with a ton of gas and running to the NDL's then its time to start diving Nitrox. Helium here is also cost prohibitive. mostly the people diving trimix are CCR Divers.
I'd love to learn more about the "helium penalty" as well. Not something that I have ever considered.
Interesting discussion, but I believe in choosing the best mix for the plan. Trimix is a tool, but not needed where another gas can be used.
I’d be interested in learning about the helium penalty. Also, with the cost of helium, does it make sense to go beyond AN/DP in OC Tech training? I’m looking at an/dp for next year and will likely stay at that level for a while.
Man I love the conversations you guys are having!
Nice discussion, I fully agree with you. There are a couple of points that I would have added though.
#1 I'm not sure whether this was just a matter of your paraphrasing or whether Ben actually made the point, but "wasting oxygen" and instead adding helium is a really bad idea. Oxygen is a sustainable resource, helium is not. We only have a finite amount of helium and using it unnecessarily is wasting it and driving the cost higher. So, I'd rather exhale too much oxygen that can be recycled in the atmosphere than exhale unnecessary amounts of helium which will be lost forever.
#2 If Nitrox is useless, am I supposed to use Trimix as a deco gas now? Like instead of a 50% stage, should I go on 50/50? 50/20? 20/80? And that's not even thinking about issues like isobaric counterdiffusion. To be completely polemic, pure O2 should not be used for deco either then, right? I mean, I want to reduce the O2 amount to as little as is required (so I don't waste any) and remove nitrogen to as much as possible, so at 6m I should deco with a minimum pO2 of something like 0.16 to sustain life and the rest should be helium then, so my new 6m deco bottle should simply be 10/90.
Never heard of this controversy, but it seems to me like everything else. Ask someone what the "best" tool, vehicle, weapon, computer, literally ANY topic...and the answer depends on what you are trying to accomplish. As an OW diver who has no interest in Tech, I don't want to have the cost of training or diving trimix. Nitrox serves my purposes as a vast majority of my dives are at locations with sand bottoms in 100 feet of water or less. No danger of surpassing the MOD, so I get the added safety margins (no chance I'm staying an hour on a single 80 at 60') with minimal cost. Got to have the right tool for the right job.
Calling it “useless” is a bit of a stretch. I would agree that it is probably oversold as a miracle gas in some shops but it definitely has its use. It is a tool with a specific use case just like trimix.
Where can I learn more about the HE penalty?
I wonder why you don’t consider diving in air and carrying an 80% O2 pony for deco at 6 meters.
Loads of people dive air with an 80% deco bottle. It's not the most common choice but certainly not eye-battingly unusual.
Most normal people gas doesnt last long enough on 20 m dive to have deco obligations
Can you guys provide the link to the podcast where Ben says nitrox is "useless?" Also, UTD offers a nitrox class, so....
Till 32m I would always use a nitrox32. Going deeper I would probably go 21/35 till 45m and then go the 18/45 till max 70, even on a ccr I would use them basically the same. Or always 18/45, from bottom till 70m 😂
Don’t set a suunto on air when going nitrox, it will go crazy after 2 days 😂
You can set an alarm for depth on the shearwater is not mistaken
Like what was said plan you dive and you know the rest
Talk about a rage bating video title
First time at dive talk? :P
Yeah, I largely come here only to roll my eyes at the content and stay in the know about the latest SCUBA memes based on them
helium is so last year, use Hydrogen.
Hydrolox diving.......
"Nitrox useless" as a claim is not a stretch, it`s simply BS. I doubt he really said that and if so in a specific context.
It`s an amazing gas, widely available and cheap.
Even if you dive deep, you want to have it as deco gas.
If you do multiple dives a day, you want Nitrox to keep your N2 load lower.
If you say it`s on open system it`s a waste of O2, i ask what your general breathing is. You inhale 21% O2 and breath out 16% O2, you useless thing!
You`d run around with your CCR all day then;)
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In a perfect world where helium supply and cost is equivalent to oxygen, then nitrox will be useless. But in the real world, nitrox is practical.