[kwirky]

i would use the underwater epoxy. super glue is meant for fine work, and you'd go through a gazillion of those tiny tubes gluing your rockwork with it.

you get aquarium epoxy from a good LFS, and except for glass (and some plastics), you can do the glueing underwater.

here's how it works:
epoxy has 2 parts. either it's a single tube, with one part on the outside, and the second part running down the middle, or there's two tubes. You mix the two together, then apply it where it needs gluing. It sets in about 8 minutes, and it can set underwater. epoxy doesn't rely on air, it relies on the reaction between the two parts. When it's done, you have something hard as plastic pretty much, but with the texture of ceramic.

Don't go overboard on the stuff. I did, when I first got it. It's tough, and you pretty much have to chip or snap it off, if you used too much.

if you're wondering how much to buy, i'd say one package of the stuff would work well if you went slow with it. Not everything has to be glued down, just the precarious work, or work that'll hold heavy corals in the future.

if it's rockwork you're setting up though for a new tank, i'd give it time before glueing everything down, so you can take it out and swish it in a bucket a week into the curing process, at least.