Wow, that's a nice tank.
If I drill my tank from the back like yours. How would the overflows be built? I mean what could I use to keep the fish from going into the holes? I currently have a 55g that I want to use as a sump for the 120, is there a way to keep the holes in the 120 blocked/closed while it's running this way I'll have time to mod my 55g into a sump and not have my livestock die on me? Thanks!