Feature Article - July 2012
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Wet Your Whistle

Improving Aquatic Safety and Aquatic Management

By Kelli Ra Anderson

"What we do is add a variable frequency drive," Caldwell explained. "We add a speed control to a three-phase motor so that instead of being wide open all the time, we can control what speed it runs at. As you slow the motor down 15 percent, I'm going to reduce energy consumption by 30 percent; if flow is reduced down to 30 percent, I'm reducing energy by 62 percent."

Proper pH, proper sanitation levels (CDC research now shows most resistant strains of Cryptosporidium require 20 parts per million for 12.75 hours in order to inactivate 99 percent), and sufficient turnover rates all play a vital role in keeping water safe. But filtration is also a vital player.

A recent study of pool filters at the University of North Carolina in Charlotte, N.C., indicates that of the sand, cartridge and precoat (diatomaceous earth and perlite) filters used, the sand and cartridge filters removed only 36 percent of Cryptosporidium, while the precoat filters removed 99 percent.

More and more professionals, like Richard Cacioppo, director at the Institute for Public Pool Studies at Princeton in Princeton, N.J., are pushing for tighter regulation because the worst pathogens like Giardia (only 3 to 6 microns) simply cannot be filtered out by the larger-pored rapid-rate sand filters used by most pools. DE filters can handle the smaller pathogens, but no regulations mandate their use at this time. "No process will entirely remove the risk," he conceded," but there are methods/equipment that will significantly lessen the risk, like pool vacuums that can filter out sub-20 micron contaminants and constant minimum filtration flow rates."

White also recommends the use of several products on the market that can help even sand filters reduce the incidence of pathogen contamination. "…[O]ne currently approved by the EPA uses a two-part system in the water and the filter," White said. "Its clarifying agent is so refined that it enhances the filtration of pool filters by holding back particles like bacteria, so when you clean the filter, backwash it, you get rid of it."

And getting rid of all aquatic dangers is really what it's all about.