16" cube ideas

[Fish]

Hey Mark and everyone. Ryan is right, my tank at home has an external overflow box that is 10" long x 4" wide x 8" tall. The bottom of the box has two 1" bulkheads in the bottom. One of the bulkheads is the drain and the other has a 5" length of pvc coming up from it so that no water goes down it unless the drain bulkhead gets plugged and the water level rises (aka backup drain). The only other thing you need is to put a ball valve (or gate valve if you can find one) on your drain line and close to valve so that the drain flow matches the output of your pump and causes the water level in the overflow box to remain somewhere between your drain bulkhead and the top of the backup.
The result is no air going down the drain and therefore a silent overflow and sump. I hope this isn't too confusing, I came across the Herbie thread one night while I was tearing my hair out with gurgling and boiling stockman and dursos - it really works. And it also happens to be the cheapest, and easiest method as well! There really are no downsides to this moethod. The key is that you need two bulkheads though - although I would never recommend only one bulkhead no matter what kind of setup you have - always have a backup drain!
I did the work on my old 20H myself and can tell you that it was quite easy to cut the overflow and bulkhead holes with a dremmle and glass cutting bit. I took the tank outside and turned the hose on a little bit and let it flow over the surface I was cutting. I probably went a little too fast and cut the 8" slot in only 20mins. At no time did I feel worried about cracking the glass but I think I shortened the life of the dremmle bit by going that fast. If you'd like I can probably drum up some photos of the job I did. I would recommend cutting a straight slot out of the back and then siliconing egg crate over it instead of cutting notches in the glass like some people do.
My nano that you posted has the bulkeads hidden in the bottom so it is visible from all 4 sides. If you are doing as external overflow box (which I would do instead of internal), I'd recommend putting a sheet of black acrylic on the iside of the back wall so that you don't see the box and plumbing when you look from the front.

The closed loop is the easy part. Just decide how much flow you need in addition to your sump return - chose an external pump that will meet those needs - put an intake line in your tank which sucks water down to the pump and then put the outlet line back into the tank. All it is doing is drawing water out and then shooting it back in, in order to increase your turnover rate.
I hope this helps.

- Chad