Salt-water pools might conjure up visions of invigorating ocean swims, but they have little in common with the briny environment. All pools need treatment to sanitize the water. Health threats of pool water include bacteria, viruses and other contaminants that thrive and grow if unchecked. Some swimmers who suffer side effects from traditional chlorination systems swear by the benefits of salt-water pools. Despite the benefits of salt-water pools, the methods used to sanitize them might come as a surprise to many.
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Salt in Salt-Water Pools
The role of salt in salt-water pools is neither disinfection, nor improvement in buoyancy. Salt levels in pools are far below the salt concentration in ocean waters. Instead, salt acts as a continuous source of convertible chlorine.
Salt-water pool disinfection systems rely on chlorine to kill germs and neutralize contaminants in the water, just as traditional chlorine-based systems. A unit containing two slightly charged titanium plates allows the salt or NaCl to pass through them. In a process called electrolysis, the salt breaks down and reforms in water to form the hypochlorous acid responsible for disinfection in traditional chlorine-based systems. Because the salt is dissolved in the pool water, there is a continuous and steady supply of chlorine flowing into the pool.
When chlorine levels fall in traditional pools, usually due to lack of strict maintenance and testing, the level of unhealthy by-products or cloramines from the disinfection process remains intact. Usually, adequate levels of free chlorine further break down the chloramines that typically cause red itchy eyes, lung irritation and the smell often associated with chlorinated pools. Salt-water pools avoid the buildup of chloramines because the chlorine levels replenish themselves constantly and do not depend on pool owners or pool workers to add more chlorine to the water as needed.
The main benefit of salt-water pools is the lack of side effects often associated with traditionally chlorinated pools. Mary Pohlman, M.D., assistant professor of clinical medicine at Southern Illinois University School of Medicine and a member of the United States Masters Swimming Sports Medicine Committee, states that in addition to irritated eyes and skin, some swimmers suffer from lung irritation and asthma-like symptoms when contaminant levels overburden under-chlorinated pools.
Even though salt-water pools might make people feel better and feel better about swimming in general, they are not chemical-free systems. Homeowners sometimes advertise houses for sale as having natural or chemical-free salt-water pools. The statement is not accurate, as salt-water pools depend on the steady and continuous flow of chlorine into the water for the benefits it delivers.