File:CO2 chart1.png

ph versus Carbonated Hardness (KH) to achieve a good and safe CO2 level for planted aquariums.

Uses the formula CO2 (ppm) = 3 * KH (as CaCO3) * 10^(7 - pH)

This formula assumes that the only buffering system used is carbonate (CO3). Use of phosphate buffers, bogwood or peat in the aquarium will make this formula inaccurate.