Using glue in your reef

[Percula9]

If you don't want to use glue.You can drill a hole into the rock and place coral.You can do both.

 

[bat21]

I have also been successful using super glue gel on top of epoxy. This allows you to to smush the glue into the tiny rock crevasses. But you need to push it down and hold it still for at least a minute or two.