So, I picked up a really nice Aqueon 180 tank, drilled two holes mounted horizontally hear the top near one end. I didn't unscrew the bulkheads when I bought it, and took it home. Tank itself is in great shape, no scratches, etc. Days later, I unscrewed the bulkheads, kinda rough under there! Heres some pics- the glass holes are 2 & 3/8 in., the bulkhead ID's are 1&7/8in. Here are the bulkheads, and the rubber was only on the outside, and no silicone was there either. I think I have my work cut out for me, no pun intended. I have to get those to seal, if they don't already, and fashion the overflow box. I'm thinking of a coast to coast, slightly slanted toward the end with the holes. Any advice on the bulkheads please?