Can't tell from the image but gasket side or no? Not gasket side I'd probably try it as is. Gasket side I'd probably put a layer of silicone and lightly snug the bulkhead down and let the silicone cure a little and tighten it up making sure the gasket side does not rotate as your tightening.
Disclaimer: I can be a bit reckless compared to a lot of folks when it comes to taking chances with stuff like this. Or may be I'm just cheap and don't want to spend money if I don't need to
EDIT : if it's cheap tank (less than $100) I
might scrap it.