I have a 15X29 IG grecian pool ~15000 gallon with 1hp pump and 200# sand filter . I had metal stains so I added 2# Vitamin C and added 2 bottles of metal free when stains were gone and 12oz polyquat 60. As far as I can tell the stains are gone but the pool is so cloudy that I can not see the bottom of the shallow end. I had trouble keeping the chlorine level up but now it seems to maintain ~0.5 to 1 ppm. There seems to be powdering sediment on bottom of pool, and when I vacuum I see it coming out of my returns. This stuff is not being captured by my filter. My chemistry #'s are Cl ~ 0.5-1 ppm, ph~7.2, alk~90. I started treatment 4 days ago, with the filter/pump on 24/7. My question is what is the powdering sediment, and how do I remove it since my filter can not. Its hoovering around 90 degrees here in the north east and my family is disappointed that they can not use my pool. Any help would be appreciate.