dun use the epoxy in the tank...if u want to use those epoxy, u have to remove the rock or coral from your tank...it can crash yr tank bcoz it may cause the water to cloud and irritate some of the corals to release "mucus"...esp some of the acropora sps and soft corals....
And after u successfully epoxy yr coral onto the rock, u cannot place them back into the water immediately....u have to let it dry first....that's y i stopped using this....
u can try bsi gel...it's a kind of super glue and it sticks real fast, within secs to a minute n does not cause yr skimmer to go crazy or cloud yr waters.