Over the wonderful winter we had in the Northeast, our pool cover failed somewhat (we use a tarp, do not have safety cover yet) and we had some leaves and debris (including a dead snake, yikes) fall into the pool and settle over the drain in the deep end. When we opened the pool the water was still pretty clear and some skimming by the pool company and a few rounds with our Polaris cleaned up most of it. However we have black stains left around the main drain. No problem, just organic stains, I thought, we can handle that. We added pool shock, kept the chlorine levels up, brushed and brushed, and no change. Then I thought it might algae, but there is no plume or cloud or dust at all when the stain is brushed like when we had algae. It may as well be paint down there for all it moves. After two weeks of this, we let the chlorine drop to zero and tried the vitamin c stain remover. There was no change.
After some reading of past threads on here and googling I thought it might be calcium scaling over organic stains but we have public water and have never had an issue with calcium scaling but I am at my wit's end so who knows. I went the pool store for help and they sent me home with descaler/stain remover. Before I dump this in my pool I thought I might see if anyone else has any ideas. I thought between using the shock and the vitamin treatment I would have seen some improvement to guide me towards using one or the other. Is it possible I would have to do multiple treatments with the vitamin c powder on a tough stain like this? This is the only stain we have in the pool from the winter. I can see why people move to the South.
We have a freeform plaster pool, it is approximately 30 years old and I do not think it has ever been replastered (we have only lived here four years). I don't know if the age of the plaster makes it more prone to staining, but as I said it is not stained anywhere else. As far as I know the prior owners took good care of the pool. DE filter.
(These are zero because I just did the stain remover treatment). I have turned our chlorinator back on so they will be going back up.)
Calcium Hardness: 230
Copper/Iron: 0 (Just had tested at the pool store)
Sorry for the wavy water, I should have turned off the pump but sometimes there are snakes back by the equipment and my husband isn't home right now. Any suggestions/ideas are welcome. Thank you!