Copper and Silver are sometimes used as sanitisers in swimming pools. In a process called electrolysis, an electrode made of Copper or Copper and Silver is placed in a return line. As an electric current passes through the electrode, Copper and Silver are released into the water. Copper and silver ions have been used as algicides and bactericides effectively in laboratory and controlled field studies. The effectiveness of these systems in pool and spa water is not as thoroughly proven, however. This is due largely to the slower kill time and lower solubility level of the metal ions. As a biocide, silver is slow compared to chlorine. In the concentrations used with ioniser systems, silver is merely a bacteriostat – effective at inhibiting the growth of bacteria, but not as effective at killing already existing bacteria. In swimming pool situations, silver alone, without chlorine, cannot kill bacteria or prevent cross infection of bathers as well as chlorine. Silver and Copper are not as effective as chlorine in killing bacterial and algae. Free chlorine is still needed to maintain proper sanitation in pool water.
Most ioniser manufacturers recommend the use of chlorine in addition to the ioniser as a back-up sanitation system. The use of chlorine can precipitate metals and cause staining. Any other chemical fluctuations or balancing addition can cause metals to fall out of solution and stain the bottom and sides of the pool. This includes shock applications, which are still necessary to eliminate undesirable compounds. Since copper is ever-present in these systems, the potential is also there for discoloration of light hair to green.
CAUTION: Never use bromine systems with ionisers. The bromide formed as the bromine is used up will precipitate both copper and silver ions, leading to staining. Use of bromine will also void most ioniser warranties.
The BioGuard Three Step Programs can be used successfully with ionisation systems. These BioGuard products supply the recommended balancing requirements as well as the supplemental sanitation called for by most of these units. Regular maintenance with BioGuard Products can help keep your pool sparkling, with or without the use of alternate sanitisers such as ionisation units.
The pool still needs regular shocking to oxidise organic wastes that build up.
The use of a metal chelant may help prevent stains. However, staining may still be a problem since metals are being added to the water continuously through electrolysis. (Check with the manufacturer of the ioniser before using a metal chelant to make sure it will not void the warranty).
