I will try to get a decent picture of this--the glare off the water makes it not show up well.
But in short, the pool sat closed for 4-5 years before we bought the house. No clue how it was winterized. It was a green/black swamp when we opened it this year. After shocking and much vacuuming, it is crystal clear now, but there is a persistent dark stain around the deep end. Basically 1/3 of the pool is about 3' deep, then drops off sharply, so the deep end is essentially a ramp from the sides down into a square level area on the bottom which is the deepest level. Right where the sloped sides meet the level floor, there is a brownish/yellowish stain all the way around that will not come off for love or money. The pool guy said he'd never seen such a thing, but surmised it might come out over time.
There are some lighter yellowish/brownish discolorations on the liner that have indeed gotten lighter over the last few weeks. We really can't go down and test in the deep end with a vitamin C pill to know if they're organic or metal , so I'm not sure if it's just permanently discolored from maybe all the maple leaves that rotted down there for years (not to mention some birds and squirrels ). Any ideas about how to treat this or test it without drowning?
Also there are a few obvious rust stains--pretty small ones--what is the best product for that?
Thanks in advance!!