Wikipedia gives me the formula (without a source) for pH (p), CO2 (c) in ppm and alkalinity in dKH (a):
c = 3a × 10^(7-p)
If this is right and I haven't done anything embarrassing with algebra, I get the more useful:
p = log10(3a) - log10(c) + 7
So a tank with a high alkalinity (10 dKH) and no more CO2 than outside air (409.8ppm) should have a pH of 5.9 which I know is wrong.
My first assumption is I made an algebra error, so I double checked this with:
Which gives me a much more complicated equation with natural logs, but I still get a pH of 5.9
I've seen tables, but having a formula for this would be useful to me.
c = 3a × 10^(7-p)
If this is right and I haven't done anything embarrassing with algebra, I get the more useful:
p = log10(3a) - log10(c) + 7
So a tank with a high alkalinity (10 dKH) and no more CO2 than outside air (409.8ppm) should have a pH of 5.9 which I know is wrong.
My first assumption is I made an algebra error, so I double checked this with:
Logarithmic Equation Calculator
Free log equation calculator - solve log equations step-by-step
www.symbolab.com
Which gives me a much more complicated equation with natural logs, but I still get a pH of 5.9
I've seen tables, but having a formula for this would be useful to me.