Yeah, it sounds like your stuck with what you got. Once the PVC is cemented it's done.
Personally I would trash the bulkheads and order up some new ones, start fresh. However, I do tend to prioritize fish keeping higher than I should. That being said, the most important fitting on your whole system is the bulkheads on the bottom of the tank. If those go bad your draining the tank to repair them. Most likely your also cleaning up a mess too
Your old bulkheads have old gaskets on them............something to think about.
Cheers!
Personally I would trash the bulkheads and order up some new ones, start fresh. However, I do tend to prioritize fish keeping higher than I should. That being said, the most important fitting on your whole system is the bulkheads on the bottom of the tank. If those go bad your draining the tank to repair them. Most likely your also cleaning up a mess too
Cheers!