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.