How frequently must pools using unstabilized chlorine be tested for chlorine?

Pools using unstabilized chlorine must be tested for chlorine levels every hour due to the inherent instability of the chemical under varying environmental conditions. Unstabilized chlorine, such as chlorine gas or calcium hypochlorite, can quickly dissipate when exposed to sunlight, warmth, and organic material. This rapid depletion means that maintaining appropriate levels of free chlorine for effective disinfection is critical to ensure swimmer safety and prevent the growth of harmful microorganisms.

Regular testing every hour allows pool operators to make timely adjustments to chlorine levels, thereby ensuring that the water remains sanitary and safe for use. This frequency is especially vital in outdoor pools, where UV exposure can significantly degrade chlorine concentrations. Thus, testing every hour is a standard practice aligned with health regulations to safeguard public health in swimming facilities.