I have a pool that I take care of that has extensive black staining on the liner. The staining is mostly in the deep end where leaves and debris accumulated while it was closed. The pool hadn't been opened for two years, and was opened again this year. There are a few small stains in the shallow end which are shaped like curled up millipedes. So it seems kind of obvious that the smaller stains are probably from metals leaching out of the millipedes and staining the liner. Is it reasonable to assume the large stains in the deep end are from metals leaching out of leaves and whatever else was sitting on that liner for two years?
How likely is it that I'm seeing Manganese staining? I'm assuming I can treat manganese about the same as I would Iron.
I added a sequestrant to the pool, and I'm hoping it will help. If it doesn't, what else should I try? Maybe Ascorbic Acid? Has anyone tried Ascorbic Acid (Vitamin C) treatments?