Chlorine has always been the gold standard in pool sanitation, but in the past several years, a supplemental option has entered the mainstream. Ultraviolet radiation systems have become a member of the aquatic ?it list.?

A range of chlorine substitutes and supplements are available, including silver and copper ionizers, according to Kent Williams, executive director, Professional Pool Operators of America in Newcastle, Calif. But they only address the need to sanitize; they do not oxidize. Williams notes that medium-pressure UV systems currently are the strongest oxidizers available to pool operators.

By exposing pool water to ultraviolet (UV) light, in combination with a chemical oxidizer, organic contaminants are destroyed. This makes it particularly useful for eliminating RWIs and chloramines.

According to the data, UV is so effective (99 percent to 100 percent) in destroying crypto, the Centers for Disease Control and Prevention recommends installing the systems, and some states and local regulations now require it. New York has made UV systems mandatory for all sprayparks.

The use of UV has changed the industry in several ways. Most obviously, swimmers and operators now have an added layer of protection against RWIs. In addition, ?it?s causing a trend back to the use of DE filters in commercial pools,? says Dr. Alison Osinski, Ph.D., Aquatic Consulting Services in San Diego. The newer regenerative systems make UV more effective because it requires clear water to work most effectively. DE-type filters can remove smaller particulate matter, which keeps the water clearer, she explains.

Looking ahead, it?s a safe bet that UV will be making waves for the foreseeable future. Still, there?s much to learn before aquatics operators can utilize UV to its maximum potential, and researchers such as Chip Blatchley of Purdue University are helping to change that. Blatchley is conducting groundbreaking work on UV and its effect on disinfection byproducts.