I am setting up a used 120g, it is a 2 overflow system, and i replaced 2/4 bulkheads. the bulkheads I replaced where both damaged, however the other two seemed good. When I water tested the bulkheads that were old (return pump bulkheads) they both ended up leaking/dripping (slowly). I have replaced the gaskets, and cannot find the exact size on amazon or BRS. I am considering siliconing the entire thing as I do not think I will be in a situation down the road were I have to mess with my plumbing again, but I still would want to go for a less permanent method. Thanks!