Saltwater pool

Salt water chlorination is a process that uses dissolved salt (2,500–6,000 ppm) as a store for the chlorination system. The chlorine generator (also known as salt cell, salt generator, salt chlorinator or SWG) uses electrolysis in the presence of dissolved salt (NaCl) to produce hypochlorous acid (HClO) and sodium hypochlorite (NaClO), which are the sanitizing agents already commonly used in swimming pools. As such, a saltwater pool is not actually chlorine-free; it simply utilizes added salt and a chlorine generator instead of direct addition of chlorine.

The presence of chlorine in traditional swimming pools can be described as a combination of free available chlorine (FAC) and combined available chlorine (CAC). While FAC is composed of the free chlorine that is available for sanitizing the water, the CAC includes chloramines, which are formed by the reaction of FAC with amines (introduced into the pool by human perspiration, saliva, mucus, urine, and other biologics). Chloramines are responsible for the "chlorine smell" of pools, as well as skin and eye irritation. These problems are the result of insufficient levels of free available chlorine, and indicate a pool that must be "shocked" by the addition of 5-10 times the normal amount of chlorine. In saltwater pools, the generator uses electrolysis to continuously produce free chlorine. It also burns off chloramines in the same manner as traditional shock (oxidizer). As with traditionally chlorinated pools, saltwater pools must be monitored in order to maintain proper water chemistry. Low chlorine levels can be caused by insufficient salt, incorrect (low) chlorine-generation setting on the SWG unit, higher-than-normal chlorine demand, low stabilizer, sun exposure, or mechanical issues with the chlorine generator. Salt count can be lowered due to splash-out, backwashing, and dilution via rainwater.

Research has shown that because saltwater pools still use chlorine sanitization, they generate the same disinfection byproducts (DBPs) that are present in traditional pools. Of highest concern are haloketones and trihalomethanes (THMs) of those the predominant form being bromoform. Very high levels of bromoform - up to 1.3 mg / liter or 13 times the guideline values of World Health Organization - have been found in some public saltwater swimming pools.

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