I've found glues to not be all the same. I cannot stand gorilla glue brand, reef glue works but takes forever to set under water. Dollar store glue to me works the best and I don't care is I burn a whole tube in one session.ya know what annoys me? Well let me tell you.
Waking up and finding one of my corals has crashed to the sandbed. This happens way too much.
I can do a lot of things in this life but apparently glueing corals to rocks isn't one of them aaaaargh
and happy Sunday
When gluing under water, I apply some to both the plug, and the rock it's going on. Seems like if you only glue onto the plug, a skim layer forms on the glue when you dip it into the water. This thin layer keeps it from actually adhering to whatever you're trying to stick it to. Gluing both, the glue actually tacks to itself and connects well.
Maybe give it a try.