“Wow, my eyes are stinging!”says a swimmer at the local pool.
“My skin is itchy!” says another swimmer.
Sound familiar? It’s hot, humid, and sunny. Everyone heads for the local swimming pool to cool off and have a little fun in the sun. But the chlorine used to keep the water safe can be a big problem for many. As a result, many pool owners, and some community pools, are converting to a salt water system to avoid chlorine.
“In five years everyone will have saltwater pools, except for the eccentric [who don’t like change],” says Bob Brooks of R&S Pool & Spa of Maryland Heights, MO, a 34-year veteran in the pool business. “The trend to saltwater began three years ago, and has doubled every year.”
In the U.S., it is estimated that the total number of swimming pools is 8.6 million, according to a 2007 study by MarketResearch.com, one of the world’s largest marketing research institutions. MarketResearch.com also estimates that the swimming pool market will top $3.8 billion for pool equipment and maintenance by 2011.
Traditionally, pool waters are treated with chlorine in the form of calcium or sodium hypochlorite, the same as the bleach used in your washing machine. The chlorine is released as the hypochlorite salt dissolves in the water. Hypochlorous acid (HClO) is the result, which kills off any bacteria or germs in the water.
“Swimmers often mistakenly blame red eyes, itchy skin and a strong chemical smell of pool water on ‘too much chlorine’,” according to the American Chemistry Council, a chemical manufacturing organization. Chloramines are the real culprit for those weepy eyes and itchy skin, says the Council. When chlorine is mixed with the body oils, lotions, spit and urine, chloramines are formed.
On the other hand, a salt water pool, which is only about 10% as salty as the ocean, eliminates the eye irritation and skin problems, claims Pentair, a manufacturing company for chlorine generators. Moreover, the water is “soft” to the touch and doesn’t have the odor associated with the usual chlorinated pools, says Pentair.
A salt water pool uses regular table salt, NaCl, to get the chlorine. The salt concentration is roughly 2800–3600 parts per million (ppm) according to Pentair, compared to the ocean at about 35,000 ppm, according to Windows to the Universe, a website supported by NASA with coverage of Earth and Space sciences. A chlorine generator uses electrolysis, passing electricity through the water, to break down the salt and form chlorine, as hypochlorous acid, to disinfect.
Brooks states that the cost for a traditional chlorinated pool is approximately “$120 per year for the chlorine and another $120 per year the chlorine shock needed to keep it up”, whereas the cost for salt for the generator is “$100 at the beginning, and between $40–50 per year afterward.”
The only downside is the cost of the generator, which is approximately $1000. Nevertheless, Brooks says that he has sold “120–130 [generators] so far this year.” With the savings from converting to salt, the money for the chlorinator is recovered within a few years, he adds.
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