Redo of bulkheads

[kien]

If they are siliconed into the tank then that's going to take some serious elbow greese to unscrew. Once/if you manage to unscrew them, replacing them should be as easy as going to the store and buying a new one :-)

.. oh, and a bit of scraping of the old silicone which is fairly easy too. I would not reuse the old bulkheads myself.