Late last summer I started getting some bubbles in the return jets. So far this year, there are lots and lots of bubbles. I can't imagine where I'd be sucking air in. To suck in air, wouldn't you also have to have a leak? The only place I see any type of leak is a slight smear of wate down the face of the catridge filter where the top and bottom is bolted together. I put more CYA in the pool Sat, so I'll wait a week before taking the filter apart for spring cleaning. Any other thoughts or solutions? Thanks.