lucafer

I have an in-ground spa along with my in-ground pool. The spa has a Polaris QT 1.5 HP blower. And it seems that it's never quite been right since it was installed. When the air exits the jets, it sometimes just bubbles up in big burp bubbles and splashes water out of the spa. In trying to see what the problem was, I removed the blower and noticed water at the bottom of the blower pipe (it was still about four feet below the blower just at the elbow where it turns to go to the spa). There also was no check valve. I added a 1/2lb check valve and the first day, it ran great. Now it's back to either generating the big burp bubbles and/or not really putting out all that much air. I drained the spa below the jets this morning and blew out the line. Not much air seemed to come out when I put my hand near the jet (no water present). Question is: do I have an undersized or oversize blower? Or is there something else that I'm missing?