Problem: not enough suction to work vacuum
Pool: 10,000 Gal., inground, w/Sand filter, Nature 2 Express cartridge and automatic chlorinator. No debris clogging air vent in pump, impeller moves freely.
The pressure on the filter doesn't want to go below 15, where last year it went down to 12 after backwashing & rinsing.
Last year, when I would set the valve for full strength suction, it would suck so hard I was afraid to put my hand near it, and it vacuumed very well.
Also, when I first turn on the filter, some water leaks out the top of it, but then it stops.
What else can I check or do before I have to call a repair guy???