What are some ways to maintain a “green” swimming pool?

What are some ways to maintain a “green” swimming pool?

—Jim Humphey, North Andover, MA

The primary health and environmental drawbacks to swimming pools are water waste, energy waste and overuse of chlorine. Chlorine is very irritating to the eyes and skin, and can trigger breathing difficulties by also “stinging” the sensitive tissue of the lungs. The chemical”s effects in a swimming pool are heightened when it comes into contact with sweat or urine. In fact, a recent Belgian study found a possible link between childhood asthma and exposure to chlorine byproducts in indoor pools.

Zodiac Pool offers a system called Nature2 that doesn’t do away with chlorine entirely but does greatly decrease the amount needed. It makes use of silver and copper to destroy bacteria and algae. Silver is a bactericide whose properties have long been known. Copper kills algae. When used together, they reduce chlorine needs by 90 percent. Another product, from ChlorFree, combines silver and copper with zinc, activated carbon and other non-invasive materials to sanitize and control algae and bacteria, and also greatly reduces the need for chlorine.

According to the National Sanitation Foundation, another substitute for chlorine is ozone, which is made from oxygen and does not degrade into harmful chlorinated byproducts in a swimming pool. The Chlorine-Free Products Association recently endorsed an ozone-only public pool built for the city of Fairhope, Alabama. The pool has been operating successfully since construction without the need for harmful additives. Ozone systems for residential pools are slowly becoming available. Sunshine Pool Products makes one that, according to owner Richard Barnes, should enable a completely chlorine-free environment if installed properly and at the right size for the size of the pool.

Pool owners can save energy while still maintaining a pristine pool by using a timer to shut off the pump for at least 12 hours of the day. To hold in heat during the night, always use a pool cover, as almost all of a pool”s heat loss occurs at the surface. By employing a bubble cover (sometimes called a solar cover), outdoor pools can also gain heat, by absorbing 75 to 85 percent of the solar energy striking the pool surface. A pool cover can also reduce water loss by 30 to 50 percent—and reducing water loss also reduces the amount of chemical water treatment required.

Besides that, the easiest way to save energy is to lower the thermostat on your pool”s heater (if it has one) so that it heats the pool no higher than a minimally comfortable temperature. Every one-degree reduction in temperature can cut your energy use by between five and 10 percent.

CONTACTS: Zodiac Pool, Inc., (800) 937-7873, www.nature2.com; ChlorFree, (506) 665-0896, www.chlorfree.net; Sunshine Pool Products, (801) 728-4520, www.sunshinepool.com; National Sanitation Foundation, (800) NSF-MARK, www.nsf.org; Chlorine-Free Products Association, (847) 658-6104, www.chlorinefreeproducts.org.