I have a Hayward s210t filter with a powerflo lx 1.5 hp pump. I just put in a new lateral assembly and sand. I followed the Initial Start Up list on the side of the filter. Once I finished it ran fine for about 5 minutes then I noticed the flow had dropped to less than half. I redid the Start Up list and it did the same thing. I can cut the power and move the valve handle to waste with the power still off, then restart, and again it will run for about 5 minutes before dropping off again.