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Examining Alternatives to Chlorine for Pool Water Treatment

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NATIONAL REPORT—There are many variables that come into play when deciding the best water treatment solution for your pool—pool size, location (indoor or outdoor), and the average volume of guests that use the water on a daily basis. Chlorine, because of its low cost, is the most commonly used sanitizer. In order for it to be effective, however, the pH of the water has to be monitored closely. If not watched properly, chlorine can cause eye and skin irritation, damage hair, bleach swim suits, and aggravate and cause asthma and other health conditions. Chlorine reacts to bodily proteins to form chloramines. These give pools their infamous chlorine smell. Experts agree that it is difficult to eliminate chlorine entirely but there are some alternatives available that can help make a pool a more environmentally friendly place for you and your guests.

According to Randy Mendioroz, principal of Aquatic Design Group, one alternative to liquid or tablet chlorine is an on-site salt water chlorine generation system. Non-iodized table salt (sodium chloride) is added directly into the swimming pool. Salt dosing levels typically range from 3,000 parts per million (ppm) to 5,000 ppm. Human tears have a salinity of 7,200 ppm (sea water: salinity of 36,000 ppm), so the concentration in the pool is relatively low. As saline water passes through a chlorine generating cell, low electrical currents transform salt into chlorine (sodium hypochlorite). Once the chlorine has killed bacteria and other organic compounds, it reverts back to salt, and the process begins again.

Despite relatively high capital and maintenance costs, the advantages of salt water chlorine generation include reducing or eliminating the storage and handling of chlorine and other chemicals, eliminating the cost of purchasing liquid chlorine, and producing water with a more natural, smooth and silky “soft water” feel. Mendioroz says there are also some potential disadvantages to using a salt water system.

“Most pool operators are not scientists and may or may not be able to handle the system,” he says, adding that one also cannot ramp up to meet chlorine demand if the pool should get busy very quickly. “We recommend salt water generators for large pools that have minimal use.”

Leased Salt Water System

David Hansen, chief engineer at the Embassy Suites Lake Tahoe Hotel & Ski Resort, says that property has been using a leased salt water system for the last two years.

“Our pool water used to be cloudy a lot with chlorine,” Hansen says. “Having chlorine transported from San Francisco was also not very sustainable. We are now spending $500 to $600 a month less on chemicals. The salt water system is very easy to maintain and our water is crystal clear. Everyone notices that the pool does not have that strong chlorine smell.”

At the Seaport Hotel in Boston, a Grander Technology system has reduced chlorine use in the hotel’s pool by 50 percent. According to Matthew Moore, director of rooms and environmental programs at the property, an electro-magnetic system changes the molecular structure of the water, improving its quality and limiting the growth of harmful bacteria. Moore says guests report less of a chlorine smell. Prior to implementation of the Grander system, the level of chlorine in the water was 2.75 ppm. Today, Moore says the hotel’s staff is able to keep it at just above 1.0 ppm.

Ozone Works Well as Sanitizer

Ozone is another technology currently being implemented to reduce the need for chlorine. Ozone does its work inside the pool’s piping at the location of the pool’s mechanical equipment. Unlike most chemicals, it does not affect the pH of pool water. Ozone is made from oxygen (O2) which is converted using electricity into O3. Ozone does carry a higher cost but it is also highly effective at killing pathogens. According to Tim Chew, an inside sales representative with ClearWater Tech LLC, ozone is “leaps and bounds” ahead of chlorine as a sanitizer. Ozone carries less of a carbon impact than chlorine because it is produced at the pool’s location. At high levels, ozone can be harmful but Chew says monitors are placed around the equipment his company sells to ensure equipment shutdown if air concentrations even slightly exceed recommended levels.

“With ozone, you eliminate most of the toxic chlorine byproducts,” Chew says.

Systems that incorporate ultraviolet (UV) light are also available to supplement the use of chlorine. In these systems, water is run through a chamber surrounded by UV lamps. UV light inactivates bacteria. According to Aquatic Design Group’s Mendioroz, UV systems are popular for indoor pools. Type of vapor and vapor pressure within the lamp itself determines the UV wavelength spectrum emitted. UV light destroys chloramines.

In looking for more environmentally preferable alternatives to 100 percent chlorine, Mendioroz says there is no silver bullet—only a “least worst” alternative. In most cases, it is a marriage of one system with another that works best—ozone with salt water, for example. Cost, access to service, and maintenance-related issues should always be considered. What one can or cannot do often depends on the city or state in which the pool is located. One should check with the local health department for guidelines before implementing any major change.

Glenn Hasek can be reached at editor@greenlodgingnews.com.

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