Chlorine dissolved in water forms an equilibrium between hypochlorous acid (HOCl) & hypochlorite ions (OCl–). See chlorination for more details.
Hypochlorous acid is generally a much stronger disinfectant. It is therefore important to estimate what proportion of your chlorine takes this form:
This calculator is based on equations and values from the “dissociation of hypochlorous acid” section of White’s Handbook of Chlorination1. It is provided free of charge and without any warranty.
1 – Black & Veatch Corporation. White’s Handbook of Chlorination and Alternative Disinfectants – 5th ed (p. 74). Wiley. Kindle Edition.