Hi all. Last weekend I opened the pool. Unfortunately there was some mud washed in the pool form heavy rain so I started up the filter and pump and vacuumed up the bottom and back washed. Left the pump running all night and this morning the pressure was about 24 (with clean filter is between 12 and 15) so I back washed the filter and put in the DE. When I went back to the pump the pressure gauge was at around zero and the pump seemed to be struggling. Thinking that something might have clogged the filter, I back washed and removed the filter cleaned and installed back. I started the pump the pressure was at about 11. I added one scoop of DE and the pressure dropped to close to zero again. Any suggestions. The pump worked fine yesterday after starting and back flushing with no problem. Any advice will be greatly appreciated.