Prepare your own DIY low cost EC calibration solutions using table salt
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- Опубликовано: 30 сен 2024
- In this video, I show you how to prepare your own EC calibration solutions. These solutions are 1mS/cm and 2mS/cm and are prepared using sodium chloride (table salt). Make sure you use regular table salt (do not use sea salt, Himalayan salt, or other types of table salt). Regular, iodized salt works fine.
For 1mS/cm add 495mg/L of NaCl, 123.75mg for 250mL
For 2mS/cm add 990mg/L of NaCl, 247.50mg for 250mL
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Class A Volumetric Flask (250mL)
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Beaker set
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Scale +/- 0.001g
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Apera EC meter
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For those of us who do not have a milligram scale, would it be OK to mix 20x more NaCl in 100ml distilled water and then get 5ml of it to mix with the proper amount of water for the final solution?
Thank you again for all you do for the hydroponic community. You've made calibrating my meter as easy as .123!
Thanks a lot for commenting! I'm glad you enjoy the videos!
I opened a brand new container of Bluelab ec calibration solution and it was way off! Was supposed to be 2.77mS/cm but it was reading 3.4. I prepared some solution according the the values in this video and it was spot on! Thank you very much for sharing this.
Thanks a lot for your comment! Very happy it worked great for you!
Thank you for all your contributions to the hydroponic society.
It's my pleasure. Thanks a lot for commenting!
NaCl is 58.44 g/mol. So 123mg NaCl topped off with pure water to be 250mL is a 8.419 mM NaCl solution which has the electrical conductivity of 1.003 in a close system and 1.004 in an open system. We had +0.3-0.4% error but good enough for calibrating. But EC is not linear with molar concentration. 247 mg NaCl in 250mL has EC of 1.965 in close and 1.966 in open system and we are going to have -1.7-1.75% error which is not acceptable in my idea as it can be easily prevented by 3.3 mg more NaCl.
Thanks for sharing!
thanks for the most scientific material online on hydroponics
Our pleasure!
Thank you so much. Very much enjoy your presentation and information.
Glad it was helpful!
Dr Fernandez, can I use these solutions on the Apera EC60 (going to buy one)? As I know the EC60 kit includes two calibration liquids (1413 uS/cm and 12.88 mS/cm) for a two-point calibration, not 1mS/cm and 2mS/cm. Thanks!
Thanks for commenting! For the Apera EC60 you will need to use the solutions they sell, since they can only be calibrated with those two specific calibration points. You can however, modify the amounts linearly to prepare solutions that match these conductivity readings.
@@ScienceinHydroponics Thanks for the info!
These 2 ECs are exactly 12.0 and 120.0 mM NaCl. EC is not linear with concentration.
Thx Daniel for this video. No risk with sodium chloride, but you shouldn't touch your nose or glasses with your gloves! 🙂 still possible with parts of your lower arm. Would you play with other chemicals, it could have consequences, so just as habit. In the worst case you remove your gloves, wash your hand and scratch the itchy part 🙂
Thank you! Not only useful for calibrating, but also for just checking if you need to:)
Hi Daniel, Thank for your share information for DIY easygoing calibration solution.. can I know conductivity for 1413us/cm required how many grams of NaCl ??
You can estimate the conductivity of an NaCl solution by using the equation: 58.44*(EC-0.0126)/117, for 1.413mS/cm that would give you 0.6994g/L.
@@ScienceinHydroponics Hello doc! can we get the source of this formula? thanks
@@raingo5625 I derived them experimentally. It is straightforward to do.
@@ScienceinHydroponics Hello Dr. Fernández. Great video on the preparation of the std. solution. I was able to do a 3,000 ppm NaCl solution for a pool salinity tester. The conductivity is high above your standard solutions, but with the provided formula, I think it is working. Like the other person, I am curious about the origin of the set formula to convert concentration of NaCl to conductivity. If you could provide how to get to it, will be greatly appreciated.
12.0 mM NaCl solution which is 0.7013g pure NaCl in 1.00L pure water.
For those who simply wanna just quickly / roughly check your salt meter… mix 5gr table salt with 1 liter of water. Reading shld be 5000
It is important to consider that this is fundamentally dependent on the accuracy of your volume measurements. If your volume is inaccurate, so will your conductivity reading. To perform this check even roughly you will need something that has a decent error in the volume reading. It is also very important to consider that this will only work if your meter's ppm reading corresponds to the NaCl standard. If your meter uses a KCl or a tap water standard this will not work and the comparison will be inaccurate (possibly very inaccurate). For this reason it is always recommended to check readings in mS/cm instead of relying on the relative ppm scales of meters.
My ec meter calibrates with 1000 ppm this method can be used if i have the brand calibrate solution for reference?
Certainly.
Do you know how to make a 256mV ORP (oxidation / reduction potential) calibration solution?
You can prepare Zobell solution, which has a potential of 220mV at 25c. Potassium Chloride 0.74%, Potassium Ferrocyanide Trihydrate 0.14%, Potassium Ferricyanide 0.11%. You need to use volumetric flasks for the preparation.
People should use pickling salt. It doesn’t have anti-cake powder and dissolves perfectly clear.
Pickling salt does work great! Thanks for the suggestion.
Good day! Thank you for this video, all your videos had been really precise and fun for me. I learned so much from your website, blogs and videos. I have a question regarding fluctuation of ec in relation to solution's temperature. Is it negligible, I am living in Malaysia a tropical country.
Thanks for commenting. The EC of solutions can change significantly with temperature, so you should compensate the measurement using a conversion chart or use a meter that has automatic compensation implemented.
Cannot understand how much water and g to make up a testing solution
Thanks for writing. Please read the video's description as this condenses some of the information in a way that might be easier to understand if you're having issues with the video.
Thank you for the information. I ordered a scale through your link.
Awesome, thank you!
Thanks for all your effort and that super DIY tutorial!
Thanks, I'm glad you enjoyed it!
Was the Water EC or PPM 0000 Before You Started.
Water was distilled water. The TDS measurement was
Hi Daniel, been trying hydro for a couple of years but only now had the confidence to jump to the DIY way and your videos and tools are much appreciated, thank you. I have one question, what can I do with these solutions? Will it help lower my tank ec values? How? Thanks again, best for you from Portugal🇵🇹
Lol, understood at the video final 🤣
Thanks for commenting! These are just to help you calibrate your EC meters, they shouldn't be used with your plants!
Dr Fernandez what is your view on Phthalates and other endocrine disrupting chemicals that are possibly leached from polymer based pipes and fittings.
You should use PVC-U for hydroponics, this type of PVC does not contain any plasticizer, including phthalates. As long as you ensure all the PVC you use is PVC-U, you are completely safe from this problem.
@@ScienceinHydroponics Thank you Dr
Is it ok to use same formula to get ec 3ms...
No. 379mg pure NaCl into (not top off) 250ml pure water will give you EC of 3.00 mS/cm which is 10 Mg more than linear prediction.
You are my favorite!
thank you!
WOW! Good job!
Thank you! Cheers!
W O W
Thanks for commenting!
Your videos are fantastic! My issue is that my tap water already has an EC of about 1300 so I a, using bottled water. That must be how people do it because unless you have a lab figure out the composition you have no idea.
Great! Thank you
Glad you liked it!