I build this With black egg crate, pond foam fish safe, added rock to foam and west system 105 to seal it. While west system was wet I put aquarium sand on it . when it dryed I shook the rest off. Here is a link the build of it.
http://www.reefcentral.com/forums/showthread.php?t=2184275
http://www.reefcentral.com/forums/showthread.php?t=2184275