Are CO2 meters/test kits necessary?

[doubleace]

The calculation that you work out must know the pH and KH reading right? And which type of drop checker you are using?

[Shadow]

The "pH op = X +.67*(Y-X)" formula is regardless the kH. You take sample water, leave it for 24 hrs (at least that what I did) then measure the pH (X). After that blow CO2 from your mouth (exhale) for few minutes, not sure for how long. what I did is stick the pH meter into the sample water than exhale into the water using straw until the number on the pH meter start dropping (Y). After than just key in the number into the formula.

I'm had 2 drop checker, once ADA and the other one is knock off verison, I think it was ANS, bought from KS at Tiong Bahru. For drop checker, you need to make kH = 4 solution to mix it with CO2 test reagent.