Water balance crucial to pool maintenance

Press, 18 November 1981, Page 33

Water balance crucial to pool maintenance

Although the spa is really a scaled-down swimming pool, it requires a lot more attention. The chemicals added must be carefully regulated in a spa because the hot water accelerates the growth of bacteria. The water in the spa is heated to a maximum of 37 degrees Celsius. Correct water balance is essential in a pool, irrespective of the disinfectant used to keep water clear of bacteria and algae growth. Supply water contains a mixture of dissolved inorganic salts, gases and, in some , areas, various organic materials. The most important of these are the calcium and magnesium salts that determine the water’s hardness, the carbonates and bicarbonates which control alkalinity, and dissolved carbon dioxide gas which produces acidity. These chemicals can coexist quite happily until you introduce something else to the water, either in the form of treatment chemicals, body pollution or simply by raising the temperature. Water balance is the relationship between the pH, alkalinity, hardness and tem.perature of the water. If water is "out” of balance it can lead to corrosion, scaling, eye irritation, haze, staining and filter blocking. The most important factor to achieve water balance is the pH control. The pH scale goes from

zero to 14. At seven the water is neutral, neither acid nor alkali is in excess. Above seven, the water is alkaline, which means it contains a greater amount of alkaline substances than acidic substances. When the pH is below seven, the converse applies. Test kits are available for determining pH, alkalinity and calcium hardness. The effectiveness of the chlorine can be lowered if the water is not balanced properly. Spa pool makers will treat a pool with chlorine and supply, or recommend, one of a variety of chlorine-based anti-microbial chemicals

that prevent bacterial and algae growth. You should also get instructions and a test kit so that you can measure the chlorine level of the water and maintain it at the correct level of one to one-

point-five parts per million or milligrams per litre. The amount of chlorine required depends on the number of people using the pool and the amount of organic matter in the water.