How does copper & iron in the water affect my pool?



While not a common problem in California, the presence of copper and iron in pool water can lead to damage or discoloration of the pool surface, and corrosion of metal components in direct contact with the pool water. Any time metal objects such as poles, toys, and tools fall into the swimming pool, they can release iron and copper into the pool water. These "local" deposits of metal could cause a discoloration of the pool surface in that area. Also, some common algaecides used in swimming pools contain moderate amounts of copper, and when used in excess, can cause staining (usually blue or green) of the pool surface. High concentrations of iron can cause general rust spots to develop over large area of the pool surface.


The Copper And Iron Scales

Copper and iron are both measured in parts per million (ppm). The scale begins at zero ppm and has no upper limit. Generally the maximum level of copper and iron concerning swimming pools is on the order of 1.0 ppm.

Ideal Levels

The recommended ideal levels of copper and iron in swimming pool water are both zero ppm, since the -presence of these metals can cause problems as explained above. However, some pools are equipped with devices, which introduce copper into the pool water in small amounts in an effort to reduce chlorine use and prevent certain types of algae buildup. In these cases, it is recommended that a copper concentration of approximately 0.2 ppm be maintained.

Time And Frequency Of Testing

Since the concentrations of copper and iron do not change rapidly under normal circumstances, testing for these metals once per month is generally sufficient, unless a copper ionizer is used as a source of sanitizer. In this case, follow the ionizer manufacturer's directions. However, if persistent general staining is observed, it is recommended to test for copper and iron as soon as possible. There is no specific time of day to test for these metals.