I used to have 10 psi on my filter. Now it is down to 2 psi recently. Does anyone know what may causing it? There is no debris around the main drains on the bottom of the pool. Skimmer is clean, too. I have not cleaned the filter for one year, but the pressure has been very steady at 10 psi. The motor sounds fine to me. I am afraid that the pipes from pool to the filter is clogged. But how likely is it? Thanks for your help.