One of the prime worries for a swimming pool owner is the possibility of an algae contamination of the pool. Fortunately, there are a number of substances available that can help keep a swimming pool from experiencing an algae outbreak. Additionally, a few swimming pool algae preventatives can also be used to kill off pool algae if they manage to contaminate a pool. As long as it's used properly, an effective pool algae preventative, as well as algaecide, is chelated (stabilized) copper.
Chelated copper is, at base, a mineral, and it's one of three different types of algaecides, the other two being quaternary and polyquat algaecides. Chelated copper can be regularly added to swimming pools as an algae preventative, though it's fine for use to kill algae that's contaminated a pool. Algae will often attach themselves to a swimming pool's walls and floors. Copper introduced to a swimming pool attaches to pool surfaces as well, coating them and killing off algae in the process.
Because copper-based algae preventatives and algaecides are mineral-based, they sometimes end up causing stains on pool surfaces. The most common staining effect from non-chelated copper in a pool for controlling or killing algae is a gray or black discoloration on pool walls and floors. Non-chelated, copper-based algae preventatives and algaecides sometimes react with water disinfectants, such as chlorine or bromine, turning to cupric oxide and staining walls. Use all types of copper-based algae preventatives or algaecides in a swimming pool by direction only.
Chelated, copper-based anti-algae formulations are not only used in chlorinated pools, but they're also favored for use in chlorine-free swimming pools. Copper is a natural mineral and is introduced into a chlorine-free or non-chemical pool primarily through ionization. Once introduced into a chlorine-free swimming pool, copper will work against algae while silver, a companion mineral, is also ionized and put into the pool. Ionized silver in a swimming pool acts as an effective antibacterial disinfectant while copper handles algae prevention.
The best preventative for keeping algae out of a pool is maintaining proper disinfectant levels. For swimming pools, maintain chlorine at one to three parts per million (ppm) or bromine at two to five ppm. Kill off a pool algae contamination through chlorine shocking, followed by a copper algaecide treatment. If you intend to shock your pool to kill algae, ensure your pool's copper levels are below 0.3 ppm before adding chlorine in order to avoid staining pool surfaces.