Chlorine is the most common chemical used to treat and sterilize swimming pool water. When chlorine (in the chemical form of calcium hypochlorite) is added to a pool, it destroys pathogens and oxidizes materials such as chloramines. When chlorine is added to water, an acid called hypochlorous acid (HOCL) and chloride ions (CL-) are produced for a week. Hypochlorous acid is what gives water the ability to oxidize, sterilize and disinfect water. CL2 + 2H2O HOCl + CL- + H2O -Equation oneHypochlorous acid then splits into hypochlorite ions (OCL-) and hydrogen ions2H2O + HOCL H3O+ + OCL-. -Equation twoOCL- and HOCL both act on pathogens in pool water, although HOCL is about eight times more effective because the negative charge of OCL- slows its ability to attack the cell walls of the pool. 'body. Hypochlorous acid (HOCL) is not. stable and degrades when exposed to ultraviolet light (sunlight) therefore ineffective when it comes to sterilizing swimming pool water. With ultraviolet light, HOCL has a photochemical reaction (photolysis).2HOC...