You may have metal in your pool water and not even be aware it. Even the smallest amount of metal can cause staining of the pool surface. Metal stains take on the characteristics of the metal. Since they have no texture, they do not brush off, at least not easily. Here are some examples of metal staining and the characteristics of each.
* Copper – green, turquoise, gray or black color stain *Iron – brownish, rust color stain *Manganese – dark brown, black or purple color stain.
When you suspect the presence of soluble metals in the water, the use of a stain & scale preventative
will prevent these metals from changing states & staining your pool. These metals can only be removed from the water by filtration. If noticed and treated quickly enough, a stain & scale additive
can lift fresh stains, but these now soluble metals still need to be removed via filtration. Since most pools do not have a filter capable of filtering dissolved metals, the use of a filter aid is typically required
. Remember, when testing water that includes surface staining, a negative metals test does not
mean that the stain is not caused by metals. Metals on the surface of the pool are no longer in the water & will not show up on tests. If you have questions, always consult your pool professional.