My tank is a strange AIO setup that poses some interesting situations as far as how to drill and plumb it. I was going to go with an overflow box, and drill the back glass, but then i got to thinking that i could use the existing weir and filter space built into the tank, and drill into that, which would shorten the amount of piping required by quite a bit. I'm fairly certain that the entire tank is not tempered glass, although i will verify that. Please take a look and let me know what ya'll think. The bio-balls are coming out, and I'm aware that I would probably have to make the weir bigger.