No Suction on vacuum

[Bnelson]

My vacuum for my above ground pool has very little suction in the hose. When I attach the vac head, the suction deminishes to practically nothing. The pumps psi is 10. Any Suggestions????

[Poconos]

For starters, some questions:
-- What is the pressure with the vacuum hose and head disconnected, that is, normal operation?
-- What kind of filter and pump size?
-- Do you have a filter valve that lets you bypass the filter? Probably labelled 'recirculate'. If so, try vacuuming in that position and note the pressure.
-- Did this problem just develop suddenly or has it been gradually getting worse?
-- Is there any air in the system when you vacuum?
-- Was there any system configuration change even though seemingly unrelated?
Answers will help us home in on the problem and the pressure tells a lot. As for possible causes, crud gooping up the pump impeller, air leak in the vacuum hose, some other blockage on the suction side.
Al