My pool was installed about 13 years ago and I have been very happy with it. I have two pumps, one for the pool/spa circulation and one for the spa jets. I also have an air blower that pushes air into the spa via about twenty small holes in the bottom of the spa. The spa jet pump motor burned out about two years ago and I just got around to having it fixed yesterday. They installed an intelligent circulation pump and a fixed speed replacement pump for the spa jets. They also installed a new intelligent controller with a remote control. Everything works perfectly except when the air blower comes on no bubbles come out of the holes in the bottom of the spa. This used to work very well with strong bubbles coming out. They did not replace the air blower and the installers did not feel responsible for this problem (and I agree). I turned on the air blower and checked below the check valve and strong air is coming out. The air blower will run for about three minutes and then shut off (probably due to overheating). It will start again after cooling down. I drained the spa down to pool water level and used a metal coat hanger to check the holes in the bottom of the spa. None seemed to be blocked. I hoped the lower water level in the spa would allow the air blower to push through, but no such luck. There must be some sort of blockage somewhere but it's a completely sealed system and there is no way a small animal could have gotten into it. I don't know what to try next and any advice is very welcome. Thanks.