The act of raising the level of hypochlorous acid (HOCl) and hypochlorite ion (OCl-) in a swimming pool constitutes a vital aspect of pool maintenance. These two forms of chlorine, together known as free chlorine, serve as the primary sanitizers, eliminating bacteria, algae, and other organic contaminants. An example of needing to execute this process is when testing reveals a free chlorine reading below the recommended range of 1-3 parts per million (ppm).
Maintaining an adequate free chlorine concentration is paramount for ensuring bather safety and preventing the proliferation of waterborne illnesses. Furthermore, appropriate sanitation levels contribute to water clarity, minimizing cloudiness and discoloration. Historically, various methods have been employed to achieve this, ranging from simple manual additions of chlorine compounds to sophisticated automated systems that continuously monitor and adjust chlorine levels.