Metal Stains

[Terry_Hope]

I visited old threads last year during pool season and read some old but good posts on using ascorbic acid to remove metal stains from fiberglass pools. It worked quite well last year but the stains are back this year. Just wondered if there was new advice on this old problem.
Thanks.

[Watermom]

Same solutions as before. I assume you fill from a well and added water upon opening? If that is the case, each time you add water, you'll need to add more metal sequestering agent to keep the metals in suspension and to prevent staining.

Welcome to the Forum, BTW!

[Terry_Hope]

Thanks, Watermom, this forum has been so helpful to me. No, I don't use well water; just city of Tulsa water and the metal doesn't register on my pool store testing but ascorbic acid really takes the stains off, for awhile. And we don't drain any water for the winter - my husband prefers to run the pump all winter.
I just wanted to make sure no miracle cure had occurred during the year while I was dormant.

[Watermom]

Oh, there's probably some snake oil salesperson out there claiming to have the cure for all that ails your pool, but ..... no. No miracle cures just yet!

[wsommariva]

I had small stains in my fiberglass pool for a few years. Asorbic acid removed them but they came back. So I bought a filter I think called Metal trap that claims it removes iron and copper from city water. I used it to top off in the spring, about 2,000 gal in a 10k pool. Iron went from 3 ppm to 1 ppm. Now I have no stains. BUT don't count on this for your situation. I don't know why my stains disappeared, just happy they did.

[waterbear]

Something else to try. If your calcium hardness is low bring it up. There is some empirical evidence that higher calcium in a fiberglass pool helps minimize stainjing and cobalt spotting. You still want to maintain a balanced saturation index so if only do this if your pool's saturation index is negative because your calcium is low.