Painting back wall

[Lampshade]

I went the ultimate DIY style... I have a sheet of cardboard that i cut to fit, painted it blue, and taped it on. It's lasted through 3 years as a freshwater tank and over a year on the saltwater now. My tank's against the wall, so I don't really care about the cardboard saying UHAUL on the back. Works well, but it also hasn't gotten wet, which i imagine would probably be the end of it. But.. if you feel creative... rockwall?

http://www.reefcentral.com/forums/sh...readid=1300282