When I built my tank it had a few small leaks as well. I used air pressure (15psi) to test it. With air pressure in the tank run water over the out side, circle each air leak till you find them all. Go back and reweld the leak and keep checking till it holds air. The sealer are good for old rusty tanks, it might not get a good grip on the new metal. Eastwood has a sealer kit if you are really interested in them. Joe
