- Water temperature (°C, °F): An elevated temperature reduces the efficiency of the chlorine and promotes the development of microorganisms.
- pH (hydrogen potential): this quantity measures the acidic or basic character of a medium. pH contributes to the effectiveness of the disinfectant.
- ORP/REDOX (measurement of active chlorine in mV): the oxidation-reduction potential, or redox potential, measures the oxidizing or reducing power of one substance compared to another. It provides information on the disinfecting power of water.
- Conductivity (μS): Measurement of the concentration of inorganic salts in the water by the ability of the latter to conduct electricity.
(1) For salt pools, salinity (more precisely the total salt content) is measured on the conductivity basis. Salinity (g/L) is used to evaluate the amount of salts in the water.