I have a spa attached to my unground pool, just purchased the house a couple of months ago and I'm having problems with the spa. Please keep in mind I'm sort of new new to this have some knolage and ideas but no way a pro. The issue is as I said no bubbles come out, the water pressure feels good. It has 5 jets (4 for the spa and 1 for regular return) I do not have a blower just a vent pipe. Dot really feel any suction going thru it. I blow air down the pipe with shop vac and and water stars to move. After that it stops. I notice one of them right after that wants to like start up (like when you crank a lawn mower) but seems very soft and then stops after a few seconds or so. The old owner had a DE filter but was changed to regular on befor selling the us the house. Is a one pump system.