[Myka]

If that was my tank I would be replacing the bulkhead with a new one with no silicone. I don't find siliconed bulkheads to be reliable long-term.

The white fitting in the photo is difficult to find - I've only ever seen it online. J&L had a version of it some time ago, but I don't remember the sizes they had. You could check there.

The threaded piece in the photo is a perfectly fine piece to use though I've found that particular piece requires a ton of teflon tape to get a good seal. Use the thick white tape if you can find it.