It seems that no matter how clean the gasket is and how tight the nut is, I still get leaks on bulkhead fittings. I've tried flipping the gasket over to no avail. This is both on the drilled 40 and on the CPR overflow I have for another tank. Is there anything you can put on the gasket to make it more water tight. I was thinking that some type of silicon lubricant would, but don't have a clue as to whether something like that would be toxic.:1zhelp: