Hello I have an in ground spa that will not build pressure on the suction side so the jets/returns will not supply water as they should. A little history first - all components are new including the pump and filter cannister. The spa is an in ground concrete spa built in the late 80's. Symptoms - with the spa filled I prime the pump and start it, initially the water comes but stops before the cannister builds any pressure so the returns have little or no water flow. The water on the suction side surges when the pump pulls water and then backs off. After several days trying to diagnose the problem I decided to install a temporary above ground suction line to the spa and when I fired the pump it worked as it should. I thought there may be a leak in the suction line but have not tested that as yet. The suction line is below a concrete deck and naturally runs under the spa. Is there any way of detecting a leak without cutting the deck and is there a solution to repair the line without any major surgery. I have heard of fix a leak but without the pump circulating water that would be difficult. Also I have heard of insertable bladders that are sent down the pipe but with so many elbows is that a practical solution
Any thoughts, recommendations or expertise to share?
Note : all the equipment is new but the lines are old except for the new fittings installed when replacing the pump and cannister. Reminder the spa ran perfect with a temporary suction line installed so all the known culprits are addressed other than the old suction line below deck. This spa has no skimmer just a main drain