Swimmers add them in great abundance. While swimming, adults typically shed a layer of dead skin cells, a pint or more of perspiration, a small amount of urine and a few grams of oils and cosmetics. This organic matter can build up to become a haven and a food source for microbes unless it is removed. Bacteria, viruses and other microbes exist naturally on most surfaces exposed to air, including water. Although many are harmless, some of the contaminants may cause infection and disease.
Disinfection is the primary weapon against microbial risk.
For more than a century, chlorine-based sanitizers have been used as a dependable, versatile and economical pool disinfectant. Overall, the use of chlorine and chlorine-related compounds as disinfectants has saved more lives than any other chemical in the history of the human race. Chlorine is a natural. Sanitizing is one of chlorine's most important jobs. Only about one percent of the earth's water supply is available for human consumption and most of it needs to be purified or disinfected.