Skimmer line partially blocked?

I have an 18x36 IG pool, and toward the end of last summer the skimmer stopped working well. The main drain pulls fine, but the pump really struggles to pull water through the skimmer when the main drain is closed. As a result, I haven't been able to vacuum this year.

The pool store that opens and closes the pool was out to check the line and couldn't figure out what was wrong. They could blow water and air through the line in both directions, and it was holding the pressure when they checked for a leak. They recommended hiring a plumber, but of the handful that I have called so far, nobody will work on pools.

Any thoughts? I don't think this is related, but I noticed the problem right after we had a new clorinator installed.

Thanks

Have you checked the chlorinator o-ring? There has been mention of problems w/ suction due to faulty o-ring. Check it, use some silicone lube, or replace if o-ring is damaged.

Just out of curiosity, is it a Hayward chlorinator?

CaryB

By any chance did the pressure rise on the filter after the change of the chlorinator? Any restriction on the either the return or suction side will affect the vacuum. If the chlorinator is an inline version and it has some sort of blockage or restriction, it could reduce the flow of water and thus reduce the vacuum.

The chlorinator is a Goldline Controls Aqua-Rite (I think it's a Hayward company). I'll take a look at it. Thanks!