I have checked in to that too, and was thinking about making some. I'd like to make a shell to cover my powerheads if nothing else. Accessable from the top but making the PH's almost invisible from horizontal angle.
I looked the other day at Home Depot for some portland cement but they didn't have any.
My LFS just got a bunch of pacific branch rock frags that is cool looking, mixing them in with the batch would really give it a natural look.
[ August 10, 2001: Message edited by: fender ]