I have a salt water above ground pool. This year I have been battling with a brown sediment in the bottom. I vacuum every day; usually straight to backwash every 3rd day and it continuously returns. My chlorine level was very high to start and is slowly coming down. All other levels are correct. I use test strips and my pool supply place numbers run very close. They said I could try algaecide but not sure if this is the right direction. They tell me to backwash when I vacuum which I have done but each morning it is there. Filter was new late last year and properly cleaned before installation this year.