It's really important to disinfect regularly your pool water in order to keep the water clean and prevent fungus, bacteria or other impurities.
How does Chlorine work to sanitise?
When chlorine is added to water, another dissociation occurs. When we add Cl2 (chlorine) + H2O (water), we get a reaction which leaves us with HOCl (hypochlorous acid) + HCl (hydrochloric acid). How much of each is created is dependent on water temperature, and especially on water pH. Hypochlorous acid is the active, killing form of chlorine. This is what does the real sanitizing work in your pool water. The chlorine molecule or ion kills microorganisms by slashing through the cell walls and destroying the inner enzymes, structures and processes. When this occurs, the cell has been deactivated, or oxidized. The hypochlorous molecule continues this slash & burn until it combines with a nitrogen or ammonia compound, becoming a chloramine, or it is broken down into its component atoms, becoming de-activated itself.