Okay I had to build this. I saw and followed the thread at RC and I sort of followed it at RF. They were both closed and I have left this thought to fester in my head. I am new to this hobbie and am shortly comming to my 1 year anniversary in the hobbie. I have built my scrubber out of a piece of tile. I figured the porous material would lend a nice surface for the algae to grow. I found a piece of tile that is almost smooth on the back. It has ridges instead of criss cross paterns. It is perfect IMO and it just so happens to be the perfect size. I have a Bio Cube 29G. The tile measures 7x9 ish. I have scrapped off the pain on the back wall so it lights up through the glass. I will post pics as soon as I can. I am still in the Fred Flinstone days of cameras and my digital camera takes 3.5" hard disks. My PC has recently suffered a problem and now I have a new lap top. Wich doesn't take those disks. Anyway I hope you can follow my design.