I've determined I most likely have a suction side leak somewhere underground but would like to get another opinion. I have a pool with a hot tub that can overflow into the pool. The hot tub has one return that's tied into the pool pump, filter, heater system. My issue is with the dedicated pump that would supply the rest of the return jets (5 or so) for the bubbles etc. The pump never reaches prime, the water flowing out of the returns trickles out. I redid the above ground plumbing on the suction side with no changes and also took apart the pump but that looked fine as well. Overnight the hot tub water level drops at least a few inches when the main pool pump is off. It then refills when the main pool pump turns on because the 3 way valve that diverts water to the hot tub never actually shuts off (another separate issue). The pumps are above the pool and hot tub. Any thoughts on how to determine where in the line the leak is? Would a camera on a long snake be effective in finding this kind of leak? Also wouldn't I see a significant amount of dirt accumulate in the hot tub when running this dedicated pump if the suction leak was underground?