Fairly accurate measurement of CO2 concentration

[Anonymous_One]

If anyone wants to know more accurate CO2 concentration in their aquarium, I recommend the Carbon Dioxide Chemical Test Kit [Hanna HI3818] (hannainst.com/hi3818-100-carbon-dioxide-test-kit-reagents-110-tests.html), which should be similarly accurate to the professional CO2 meter OxyGuard (which costs $3,332!) => see 2hraquarist.com/blogs/choosing-co2-why/co2-fine-tuning-3-techniques. I bought one myself and tried it in my last experiment. It costs $33, but it should last for about 110 tests (so $0.3/test). The reagents [if new] last about 5 years.

 

[Jeff Miotke]

At the price, I jumped on this as well when Wong posted his paper on measuring CO2 levels in an aquarium. I've been using it for a few months now.

 

[Anonymous_One]

Just to add, the accuracy of the measurement in this method depends on the amount of aquarium water sample used. If we assume a lower CO2 concentration (e.g. in the range 0-10 ppm), we use a 50 ml sample. This gives a much higher measurement accuracy (on the order of tenths of units), but in turn results in a higher consumption of reagents. For example, I got a concentration of 4.2 ppm in one of my experimental non-CO2 aquariums.

 

[Naturescapes_Rocco]

Just picked one up. Interested to see how well it works! Will be testing on a 150cm tank with a horizontal reactor.

 

[BenB]

Back in the old days, ... ugh.... LaMotte made the gold standard aquarium test kits. They were expensive. I bought the CO2 kit. I enjoyed knowing exactly how much CO2 I had, but I don't recall that the knowledge made any difference in my growing abilities or the health of my plants. Drop checkers weren't a thing yet nor the 1.0 pH drop. We used the ph/KH table. LaMotte still has some of the best stuff, but we all seem to be getting along fine without it. Link to test kit HERE

 

[Kwyet]

I’m just bought the Hanna one, but today they said it’s back-ordered. It’ll be interesting when it comes though. I read an old post on another forum recently that said the pH drop method could be wildly inaccurate because there’s different amounts of atmospheric CO2 depending on factors like city or rural location, pollution etc. I don’t know, but he seemed to know what he was talking about.

 

[Anonymous_One]

I'm still planning to test it, but it seems to me that the contents of the measuring kit are (1) a standard 1% phenolphthalein solution and (2) a standard 0.1 M NaOH solution. Anyone who would like to save significantly can order just these two solutions + a small 50 ml beaker (for the aquarium water sample) + a dropper bottle (for the phenolphthalein) + a suitable syringe or pipette (for the NaOH titration).
PS: Here in Europe (Czech Republic), you can get 500 ml 1% phenolphthalein + 1000 ml 0.1 M NaOH for under $10.

 

[Anonymous_One]

NOTICE: Given my severely limited ability to communicate with others via social media in today's world in a way that is mutually agreeable and does not lead to conflict (I've tried many times and always failed), I prefer not to participate in any online discussion. If you have any questions or would like to discuss other matters with me, please use the mail channel: golias.net/akvaristika/contact.php.

 

[Naturescapes_Rocco]

Just got my Hanna kit today! Ran a few tests, will compare more tomorrow.

 

[BenB]

Just got my Hanna kit today! Ran a few tests, will compare more tomorrow.

Did you find anything interesting?

 

[Naturescapes_Rocco]

Did you find anything interesting?

I actually started a whole thread!

Hanna CO2 Test Kit: My experience so far (and why you're probably not starting CO2 injection early enough)!​

 

[BenB]

I actually started a whole thread!

Hanna CO2 Test Kit: My experience so far (and why you're probably not starting CO2 injection early enough)!​

Cool, I hadn't seen it. I'll check it out.