I had another tank that did the same thing Mark. Greywolf's method worked on my first tank but I just couldn't stop the second one from leaking. I figured it was a mess anyway so what the heck, and I took the gasket right out and put a thicker coat of silicone on the inside of the lid and that seems to have worked. I don't know how long it will last but I have lots of silicone left in the tube so I can always scrap out the old and reapply if necessary.