Saltwater-SAFE rock...

[kittyhazelton]

I am trying to figure out what the best way to make a large rock structure in a SW fish-only aquarium would be. I am not looking to have any plants/inverts/corals or anything like that, just want to have something to give the tank structure as well as provide security and hiding places for the fish.
I would like to know what kinds of easily available and cheep rock are ok for a SW aquarium. What have you experimented with? I was orriginally thinking of creating a big artificial rock structure with plastic resin and mixing in sand/gravel/mixed shells to make it look more "natural"
The structure I want to make I want to have about 2ft high, by 3ft long, and about 1ft at the widest point. Making it light would be a plus.

 

[stephclay]

use lava rock. get about 100 lbs for about $15. just make sure that your sand substrate is aragonite. Lava rock will lower pH slightly, while aragonite acts as a buffer to a pH of about 8.1
then get a few peices of live rock, add calcium and a dkH additive and watch the purple corraline aglae grow. in 8-12 mos all rock will look as it came from the best oceans!
good luck and have fun

 

[BIGgourami]

i don't like lava rock, you never know what kind of elements or minerals are in it that may leach out.
i prefer sand or lime stone, or basically anything calcerous.