I'm am amazed that I just fixed some leaking PVC with a shop vac!!! I had a leak where the union meets the return. This tank had 4 leaks in the plumbing and 3 were solved by simply adding more pipe thread sealant. This last one was on a slip fitting, what the heck! I took the part off, capped on end, and put a shop vac on the other end. With it running, I added primer and cement to the leaky area. The vacuum created pulled the primer and glue exactly into the areas needed and there is no more leak!!! Check out the vid where I got the idea from...