Tube of Duro Quick Gel No-Run Super Glue with cyanoacrylate... ...Ace Marine Epoxy--Sets in 10 minutes but under water longer! The dispenser dispenses equal parts of epoxy and hardener!)
Take the two- part epoxy back and ask them to get you some Ace Plumber's Epoxy Putty
, their part number 48526, UPC No. 0 82901 48526 1 . This is the same underwater epoxy putty that is sold to the hobby as Aquastik, etc. Use it after about 5 minutes of mixing (out of the water) to stick rockwork together or to mount stony corals or large stony frags to rock (or large stony coral specimens). It will require some method of holding the specimen in place for about 5 minutes, but will set in that time and will accept coralline growth within a few weeks. The putty will get warm when it is ready to use, but will start to set quickly once it starts to cool in the water.
The cyanoacrylate gels can be used to mount stony frags or softies to rock. Pat both pieces dry (the rock and the specimen). Apply some gel to both pieces, wave them in the air for a few seconds (8 to 10, then press them together and hold without shifting for 30 seconds. This will adhere the two together, but will not be fully cured for about 5 minutes. Exposure to SW in that time is OK, and may accelerate curing, although this was related to me by others (and I have not personally seen this happen).
I have been told that the gel may be applied underwater and used without exposure to the air, but I have had little success with this. I have actually glued Xenia spp.
with the cyanoacrylate gel and had them hold using this technique. On purchasing the gel, unless you have a propagation party or are planning on doing a large number of frags, I would buy the little 1/8 oz tubes, as they are pretty much unit-of-use for 5 to 10 gluings, and you won't have to worry about the glue hardening in the dispenser. The large 1 oz bottles are great when you have a large specimen that will breakdown into more than 15 or more frags. If you are moving a large tank or a large number of specimens, I would go ahead any plan of having some accidental frags. for this, go ahead and buy the big bottle and prepare some agrocrete plugs or use the frag plugs that Cyberchef has available, as they will fit into the openings in eggcrate and will allow you to organize your frags into a small compact area.