Reference KH for target CO2 calculator

This calculator allows you to make a reference KH solution for a CO2 drop checker using some container, NaHCO3 (baking soda), Bromothymol blue (such as from a low-range AP pH test kit), and any target CO2 ppm. Keep in mind that this target should be the perfect green on your drop checker (6.6 pH). This calculator assumes humans can see "green" at +/- 0.2pH.


So, if we use that assumption with two drop checkers, we can calculate CO2 to +/- 2.5ppm.


My target CO2 is ppm
I have a Liter Gallon container to mix with (recommend at least 2L)
I have one two drop checkers.