On my nano tank, I have a bulkhead drilled through the tank wall as the overflow to my sump. The problem is, it doesn't really overflow, unless I want my tank water level real low. One solution is to put a PVC elbow in the tank to drain water from the surface, but this is a bit obtrusive and ugly in the tank. My boss and I built these small boxes out of acrylic to solve the problem w/o looking too weird... Front to back, it's about the width of my pinkie. It just fits over the bulkhead. Attached is also a pic of bleeding blue's new A. frenatus pair. I hope these help someone or at least give new ideas...
Matt
Matt