Here is an easy DIY for a nano. This one starts with a Marineland Eclipse 6 gallon, which was chosen because of the easy-to-access hatch on the top:















First thing you need to do to the filter box is cut out this section, using a Dremel cut-off tool, or even a soldering iron:










Doesn't need to be a smooth cut, since water will be draining down through the holes anyway.
Now, test fit the filter box on the back wall:







Looking from the backside, see how the filter box will set on the wall:






use a little bit of scrap plastic to raise this side a bit:






Now, epoxy some plastic sheet (I just cut them out from the hood material) onto the filter box so that it will hook onto the wall; the epoxy will also hold the little plastic scrap in place too:









Mounting done:








Now cut a piece of hard plastic (any color, any thickness) to fit in the filter box. Use sandpaper or a drill or a file to make the surface rough:






Now cut a piece of "Rug Canvas" or "Plastic Canvas" (found at any sewing or craft store, or online) to fit on the backing:






Rug canvas is preferred because it lets the algae to attach better, but since rug canvas is flimsy, you'll need to epoxy it to the backing. Plastic canvas (pictured) is rigid and can just be set down on the backing, but it does not hold algae as well.

Here is the screen finished. Water should flow off the edges and drain out, but if it collects and gets too deep, cut a little section as shown and it will drain out rapidly:






Attach your light; a halide was chosen so as to get good growth, easy attachment to the tank, and strong lighting for corals:






Here is the screen with a fews days of growth (food was put into the water to rot):






A few more days:






Begin to do your weekly cleanings, 1/2 per week:






Cleaning video:
http://www.radio-media.com/fish/6galCleaning.mpg


If the pump ever stops, turn it over and remove the round part, and check to make sure the little wheel can turn freely:









Pump check video:
http://www.radio-media.com/fish/6galPumpStop.mpg


That's it! Post your nano scrubber pics!