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What to use to disinfect, oxidize pools & spas

By Marcelle Dibrell

The overwhelming majority of swimming pools in the United States are treated with one form of chlorine or another. 

That’s because there is no question as to chlorine’s ability to oxidize and disinfect. As a disinfectant, chlorine kills bacteria, algae, and pathogenic organisms. As an oxidant, chlorine combines with other compounds and destroys them.

And in addition to chlorine, the market is also flooded alternative water sanitizers and purifiers that promise to bring a nominal chemical load and at the same time keep pool water sparkling clean. Such systems are particularly attractive to the environmentally conscious, who believe they are investing in chemical-free water maintenance. While manufacturers of alternative sanitizers will sometimes claim that their systems are chemical free, except for the use of UV light alone, all systems employ some combination of chemicals. To provide a safe swimming environment, both disinfection and oxidation must occur. 

There are numerous ways to accomplish this. Traditionally, chlorine has been used to do both functions. Bromine, like chlorine, can also accomplish both. In 1977, biguanide — the first and only non-halogen sanitizer — was brought to the market. When combined with hydrogen peroxide, biguanide both disinfects and oxidizes. 

The EPA also recognizes certain metal-based ionization systems used in conjunction with monopersulfate for spas, however halogen residuals may also be required.

Other metal ion systems, as well as ozone, and UV, while not approved as stand-alone disinfectants, can be used with supplemental disinfectants, potentially lowering the quantity of chemicals used. 

But when considering alternative sanitizers, it’s important to compare them to well-maintained, chlorine-based systems. 

Most of the complaints concerning chlorinated pools — such as chlorine odors and skin and eye irritation — are caused by chloramines, not chlorine. 

A well maintained chlorine sanitized pool does not have these problems.

In this issue we will look at the benefits of the various sanitation systems that are available. And while there are many commercially available sanitation systems and supplements, today, we will look at chlorine, metal ionizers and biguanides, ozone, and UV. 

Paid subscribers have full access to the complete coverage on pool and spa sanitizers. Contact our circulation department at 949-916 0292 or email for details.

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