I have a sand dollar SD35 sand filter with 1 hp dynamo pump that is brand new and has just been installed. The filter media that the dealer sold be was zeosand 50lbs. Some of this filter media was lost during installation. My pump is currently operating on the filter setting at about 8 psi. We first noticed that there may be a problem when we attempted to hook to a lil shark pool cleaner. The filter would run for a few minutes and then it would lose pressure down to 0 psi and water began leaking out of the backwash. The automatic pool cleaner seemed to be working and no air was noted in the system. Could this be related to the filter media or could something be wrong with the filter itself? What should normal operating psi be?? .