Foam Aquascaping?

[jgoldsney]

I have done the back of my tank with the 'Great Stuff' expanding foam. What I did was make a base out of egg crate with some egg crate shelves zip tied to it to make ledges. I then sprayed the structure with foam. To get ridd of the "turd" look I dropped handfulls of sand and coral chunks on it while it was still wet. once it dried I sprayed it with multiple coats of Krylon Fusion black paint. It is now quite covered by coraline and you can hardly tell that it is not rock.