I am at my witts end with my sand filter not filtering properly . I have recently changed the sand , the lateral , and the valve head . I can vacuum with a panty hose over the vac plate and pic up alot of stuff i thought the filter would catch , but 6 or so hours there is dirt all over the bottom of the pool floor . i have vaced on waste and filter because i know it is not algea but i am tired of dumping water out for no reason . There is no construction going on near where i live for the air to bring it in . I really just dont know !!! My question is this , how small of stuff can the sand filter actually filter ? This problem has been going on for 2 yrs or so and i am ready to give up on a clean pool . I have spent countless dollars on yellow out because everyone said it was mustard algea . I just dont know , please help