when using floc it's IMPORTANT that you let the stuff settle, then vacuum to WASTE, and slowly, so to not stir it up into suspension. Do not vacuum to the filter. If you have a sand filter, and the dead stuff is too fine it'll just land up blowing it back out the return and give you a cloud. As far as the white buildup, im a chlorine user, so i'm not sure what thats all about, maybe some chemical reaction to your sanitizer. There may be a specialized floc for your type of sanitizer thats different than the one for chlorine pools. Hope this helps......