I wanted to build a refugium for my 10 gallon tank and saw an interesting DIY on nano-reef (direct link to the DIY is here http://www.nano-reef.com/forums/index.php?showtopic=30154&st=0. Unfortantely, I don't have any pretty pictures to show. Look at the topic there and you can see some. I'll just post my steps. 1. Buy the Aquaclear 500 or renamed to 110 (This is the largest one you can find from Aquaclear) You will be looking at about $70 or so if bought at PetsMart. 2. Tear everything out of the thing (sponge, basket, etc) 3. Take a piece of Plexi/acrylic/other plastic and cut it to a 6 inch height to create a baffle. 4. Use some type of sealant or glue to put the baffle in. I recommend putting it at the 2nd notch away from the pump. I put mine too close to it and it wasn't pretty. 5. Take the big part of the filter basket and measure/cut to fit over the water return. This will keep fish and macro algae's from getting in or out of the refugium. Glue this into palce. 6. Make sure the glue/sealant is dry before you do this. For a sand bed I put about a 2 inch sand bed. I also added about a pound of rock to the refugium. Note that this thing is pretty big, It'll take up almost all the room on a 10 gallon tank. Luckily, If you made enough room you can place your heater inside the thing. However, you will need to make a hole for the chord of the heater. Lighting options: I've read many different ways to lighting this thing. Some have taken desklamps and cut a whole over the lid. personally, I went to Petco and found the shortest flourescent strip light, 12". Fixed it with a daylight rated flourescent and just plopped the thing ontop of the refugium. I have only had the thing running about 3 weeks, but I did see growth on the Chaeto (just bagged a clump). Well, I don't know how useful this will be without pictures. Hopefully the reference post will give you an idea.