My Polaris 480 w/ booster is running too slow. I checked the water pressure coming out of the wall and it seem normal (i.e high volume w/ booster pump). The back up valve seems to be working normally, where water shoots out when backing and nothing come out whe running foreward. There are no leaks in the hose. I replaced all the belts last at the beginning of the season and the wheels all turn. But it is really crawling slowly and , there doesn't seem to be a tremendous amount of pressure coming up through the venturis. Although I'm not sure aboput that as I never paid too close attention before. There is enough pressure coming up through to have tha bag standing straight up and it is picking up debris, but it is definetely moving cery slowly.

Any Insight?

Thanks in Advance