Analysis of free and combined chlorine concentrations in swimming pool water and an attempt to determine a reliable water sampling point

The analysis of free chlorine concentrations in swimming pool water makes it possible to assess the antiseptic effect of the disinfectant. The concentration of combined chlorine determines the comfort of swimming and indicates if there is a threat from DBP (disinfection by-products). The distribution of free and combined chlorine concentration was analyzed in four basins differing in seasonality of use and in the applied water flow systems. After considering the distribution of free and combined chlorine content in characteristic points of pools, an attempt was made to determine the most reliable point for assessing the quality of water and its suitability for swimming. Such searches should aim to identify the places with the worst water quality. The most uniform distribution of the concentrations of both free and combined chlorine was observed at the middle point of swimming pools, while at points near the corners and walls of swimming pools a varied distribution was observed. Such a control strategy, based on the least favorable test results at a point considered as characteristic, would make it possible to verify the parameters of the swimming pool water treatment system and thus minimize the risk to swimmers' health.