Shortly after I closed our in-ground pool last fall and put on the winter cover, there was a wildfire close to our house that put a lot of ash into the pool. I opened the pool a couple of weeks ago to find that at the deep end the ash seems to have stained our year-old Pebble Fina. I contacted the outfit that plastered the pool, and they just suggested using coarse sandpaper on it. I tried that on some wall stains, and it does work. But this is going to take a while and will mean draining the pool to get to the bottom at the deep end. Anyone have any other ideas - perhaps a chemical solution? To make matters worse the wheels of my Polaris cleaner have also collected ash on them, and it's leaving black streaks when it makes sharp turns.