Acipenser 2012 nano contest entry.

[Enigma]

Hmm. Based on the photo, you're going to need to run the skimmer in your display. The water level for the skimmer should be about half way up the vents on the front at that top.

And, remember that you're going to have to leave enough room in the sump for the water to drain from the display in the event of a power/return pump failure (or if you just decide to turn the pump off). You can limit the backflow by ensuring that your returns are above the water in the display.

You may be able to fab something up that will let you use the skimmer in the sump, but I'm at a bit of a loss as to how it could be done.

You can check glass-holes.com for your holesaw. I've ordered from them in the past, and I've been pretty pleased with their products.