EcoTech Coral Glue: this is one SUPER glue!
You may know it better as “super glue” or even "frag glue." After experimenting with many different brands of cyanoacrylate, I have discovered not all cyanoacrylate are created equal and some are clearly better than others.
At the top of my list is Coral Glue from EcoTech Marine. I have been using Coral Glue for a few months now and have been very happy with the results. Not only is it extra thick, it also sets quickly and holds extremely well—all properties I look for in a great glue to attach my corals.
The trick for working underwater is to put an ample amount of glue on the coral or frag disc/plug, then rotate it from side-to-side it as you press it on to the live rock. After 10 seconds or so, the glue will begin to set. You may notice strings of glue and feel it start to "grab." Once it grabs, you can then press down and hold for a few seconds while it fully sets. A toothpick works well for cleaning up excess glue.
Unless you are planning to frag a ton of corals, I recommend the smaller 30mL bottle over the larger one as the glue does have a shelf life of 1-2 months after it has been opened. At $9.99 for a 30mL bottle of cyanoacrylate (which is equal to more than 7 small tubes), EcoTech Marine Elements Coral Glue is a great value.