Frustrated with leaking bulkhead

I have a 150 gal. It has 3 holes. I can get 2 of the bulkheads to seal but the one in the corner keeps leaking. I’ve dried it, wiped it, changed rubber seals. I’ve tried teflon tape and a yellow sealant t thing .

Correct procedure is
1. Dry and clean all dirt dust from glass
2. On water side is a bulkhead and rubber seal
3 rubber seal has 2 ridges on. One side and flat on the other. The flat goes against the bulkhead and ridges go toward glass
4. On the outside is another gasket and nut
5. Use sealant or teflon tape
6. Tighten with fingers until you can’t anymore
7. Use wrench and tighten another 1/4 turn
8. Wait 12 hours before adding water

What do I try next? I’m about to call a plumber to do it cause my wife is going to make me get rid of the tank if I keep swearing at it. Did I do something wrong?


I am trying a herbie setup I think it is called. A short return tube that runs to a rollmat filter. The sump has a giant sponge filter with a return pump to tank. The third hole is for an emergency overflow.

Have you tried using a different bulk head fitting? Sounds like it may have a problem if it keeps leaking yet the other 2 are fine.

I had one once witg bad threads .

Al

I'm thinking the same thing Al - wonder if it's a bad fitting. If it's a fitting that's been reused, could it have possibly been cross-threaded? If you accidentally cross-thread a PVC/ABS fitting like a bulkhead, the threads are shot and won't seal regardless of how it's installed.