Great tank. I hate bulkheads but figured out a quick fix. As silly as it sounds over tightening can cause more harm then good. I take the rubber washer and apply a light coating of Vaseline or petroleum jelly to either side. I them put it on the inlet side of the bulkhead. Put the bulkhead through the hole and follow it by the nut. This where you make or break it. I hand tighten it snug then give it one good twist. If you try this with out the Vaseline the rubber washer tend to deform in one spot. Hope this makes sence and helps you?
Its gonna be replaced soon.