CO2 Equilibrium

The following graph shows equilibrium pH, alkalinity and hardness of DI water into which calcite has been placed as a function of the partial pressure of CO2 over the water. To convert hardness and alkalinity, here represented in mEq/L, to ppm as CaCO3 multiply by 50. Ionic strength effects have been ignored.

Co2pH© A.J. deLange 2013