I have a 3-way pentair diverter valve that when rotating the handle to one side, the basket connected to my pump starts filling with air, so I am assuming it is a vacuum leak. I thought it might be a leak in the valve itself, so I bought another valve, pulled out the guts and placed them all in the old valve housing. The problem still exists. So now I'm guessing it is either a crack on one side of the valve housing or the 2" suction pipe that leads to my pool. That suction pipe leads to my pool vac inlet and is about 12" below the water line. When my pool was built, I watched them pour slurry over all of my pipes and there is a concrete slab over 95% of the pipe run so if there is a crack in the pipe, I'm hosed. What is the best way to find out where the leak is? I'm thinking about getting a rubber plug to place in the pool vac inlet, drilling a hole in it, and hooking up an air pressure line to it. Then closing all the valves adjacent to the one I am troubleshooting. I can then fill the pipe with air and look/listen for any leaks. Does that sound reasonable? Any help will be greatly appreciated. Thanks, Kory