I don't think I can remove the rock I want to place it on. would it be safe to do it underwater. place the glue on the back of my coral rock and then place it in the tank fast to the rock and hold it for a second?
Superglue gel will work fine for what you want to do, I use it underwater all the time. Go to Home Depot, Lowe's or Ace for epoxy. It's a fraction of the price that the LFSs charge. Just look for a brand that says it's safe for potable water and you will be fine.
I got some 2 part epoxy that turns purple like the agle on the rocks. stuff works great. yea well I tried to put it were I wanted it and wedge it in but something knoced them over during the night. o well. it aint moving now
putting glue down on the a small piece of rock and then the coral to the rock seems to work OK. That way, you can still do a bit of aquascaping without being limited.