Last year my inground pool started shooting dirty water back in to the pool when I vacuum it. I have tried everything. First I replaced the sand, then I replaced the valve head on the filter. I got a new pump last year. I can vacuum on waste, but I lose 3 or 4 inches of water before I even get done. Does anyone have any suggestions? It acts like the filter isn't working quite right. The pool water is finally clear, but I have a layer of algae on the bottom I need to get rid of. Thanks!