Planted Tank Guru
Join Date: Dec 2002
Location: Portland Orygun
The pH/kH/CO2 chart is based on the idea that the ONLY buffers in the water and bicarbonates and the ONLY thing used to lower pH is CO2.
The acids that you get when filtering with peat throw the whole equation out the window.
It's possible to guesstimate your CO2 levels if you know the starting pH of the water. The pH after being filtered though the peat and the pH drop after you inject CO2. But at best it's a true WAG.