Hello everyone. Long time lurker, first time poster. The past few seasons I have battled with a problem, and not sure I really know what I am dealing with. I have this brownish-grayish "Stuff" in the bottom of my pool. I replaced my sand filter filter last year because I was told I had a broken lateral and sand was being passed to the water, (plus the filter was 15 years old,) but that didn't solve it, although it did seem to correct itself over the course of last summer, (but I don't know why.) But its back, and is proving to be quite a nuisance - and challenge to get rid of.
It looks like sand, but is not gritty - in fact, you cant even feel it at all. As soon as your finger gets close to it, it puffs away into water, making it a little cloudy. Doesn't feel slimy either.
It comes back within 24-48 hours of brushing pool, and for the most part, shows up in the same places.
So far this year, I have vacuumed to waste 8 or 10 times, but it always comes back.
My pool is shaded due to trees, so never really gets full sun, so all sides are the "shady side."
Most recently, I thought it might be mustard algae, so used Yellow Out, (I know, I know,) and then kept free chlorine at 15+ for 3 days. I am on day 4, with little to no improvement.
Any insight extremely welcome and appreciated!
30k Gallon Vinyl
Borates 20 (still working to increase)
Filtration = Sand Filter