Originally Posted by sign guy
simple and quick questian. just wanted to make sure that the gasket goes inside the tank
Not always.
The gasket always stays with the flange of the bulkhead and opposite the nut. Usually the nut is on the outside of the tank, and therefore the gasket is usually on the inside. Sometimes its necessary to mount the bulkhead in reverse.. Sumps for instance.. Then if the nut is inside/on the wet side, and the flange is on the outside/dry side, then the gasket goes on the outside/dry side with the flange.
If you have the gasket with the nut, and not the flange, water can leak/seep through the threads and past the gasket. But if the gasket is next to the flange and squeezed between the glass and the flange, water cant get passed, no matter wether the gasket is on the wet side or the dry side