Phosphate in swimming pools, coupled with sunlight, fosters algae growth. Small amounts of algae are introduced into pool water in various ways, such as on fallen leaves, and phosphates are nutrients the algae uses to grow in the pool water. Removing phosphates from pool water can be done without using special chemicals.
Reduce Organic Matter
Phosphates come from the breaking down of organic matter in the pool water. Dead leaves, insects, perspiration, human skin cells and even rainwater produce phosphates upon decay. One way to reduce the level of phosphates in a pool without using chemicals is by taking precautions, such as showering to remove dead skin and sweat before going into the pool. Some fertilizers contain phosphates for plant growth, so do not use these fertilizers around the pool area. Winds can blow fertilizer residue into the pool water.
Skimming the pool regularly and cleaning the skimmer out helps prevent organic matter from decaying in the pool water. Vacuuming the bottom picks up sunken decaying matter the skimmer missed. A pool cover helps prevent debris from entering the pool, but the owner must remove the cover correctly; otherwise, the matter on the top will slide into the pool. While a water filtering system reduces phosphate levels somewhat, the method isn't entirely effective on its own. The dying algae in the filter releases phosphate back into the water. Check and clean filtration systems regularly.
Decks and other raised areas around the pool can be a source of phosphates. Covering the pool when cleaning a deck or raised area can prevent runoff of water and debris into the pool.
There are special phosphate-removing products on the market if the pool already has a severe phosphate problem. Both aluminum and lanthanum-based products remove phosphate from water, with lanthanum compounds being easier to use. Some pool testing kits can test phosphate levels. Levels higher than 2000 parts per billion might require the use of an aluminum or lanthanum-based remover.
"Shocking" the pool is a common home remedy, as most pool owners have chlorine on hand. The owner puts a large amount of chlorine, a short-term algaecide, into the pool at one time. Although the shock will kill off some algae currently in the pool, the chlorine will not reduce the level of phosphates. Once the chlorine level drops, the phosphates will provide the conditions necessary for algae growth again.