Drop Checker Accuracy vs Kh/PH method

[Kramer]

Hello, I was wondering if anyone has noticed a difference in reading co2 from the level indicated by a drop checker, and comparing that with a measurement using the Kh/Ph method.

After reading some threads, I want to get a drop checker. Also, my LFS (big als) sells the Red Sea CO2 Indicator. This is a drop checker? And I was wondering if anyone knows at what level is it calibrated to indicate a good co2 level? Also can I change the reference solution in it and use the method given in the sticky?

So if anyone can answer those questions I would appreciate it

 

[rkilling1]

After reading some threads, I want to get a drop checker. Also, my LFS (big als) sells the Red Sea CO2 Indicator. This is a drop checker? And I was wondering if anyone knows at what level is it calibrated to indicate a good co2 level? Also can I change the reference solution in it and use the method given in the sticky?

I use the Red Sea one and don't have any problems with it.

You can get certified KH standards here:

http://liquidarthome.net/khstandard

I ran a KH test on the KH standard and it showed up as 4 just as it should have, but I have never checked the difference between pH/KH and the drop checker.

Even if my aquarium didn't have anything that would distort the results, you need a more accurate test kit to be able to measure CO2 effectively. ie having a KH of 4 in your tank means it's between 3 and 5. It doesn't mean it is exactly 4.

Lets just say my pH kit is 100% accurate, if I use the pH/KH charts and knowing that my KH is between 3 and 5 I would end up with:

A CO2 of 22.6 is I use a KH of 3 and a CO2 of 37.7 is my KH was 5.

That's a 15 PPM difference. Quite a margin of error. If I were to take out the KH error, my error margin decreases dramatically. This is the main reason for using a drop checker and a certified standard. I know, within a small percentage of error, what my CO2 really is.

There is no reason for me to check the KH/pH vs drop checker due to the wide band of the KH test kit. (Granted you are still using the KH/pH chart with the drop checker)

 

[Purrbox]

The greater level of accuracy is acheived when you use a KH reference solution with a drop checker. Most commercial drop checkers, like the one by Red Sea, recommend that you use tank water in them. This is no more accurate than testing your water. It's when you have known KH value without any buffers affecting the pH/KH relationship that the accuracy is improved. The other benefit is that you can determine you levels with a quick glance instead of having to drag out your test kits.

 

[Kramer]

egads, a margin of error 15ppm? 8O I wondered about my Kh test accuracy.

So ill need to get a different Kh reference solution for this red sea.. alright sounds like a fun project! unless the lfs sells it, i dont want to buy it off the net i want it NOW! lol

Thank you for the advice!.