Bubble coral location question

[Reef Pilot]

I have mine both on the sand and on the sides of rock, both locations are fine. On the rock, though, they will grow and attach themselves pretty solidly, making them difficult (or impossible) to remove without chipping off a chunk of rock. On the bottom, they "shed" sand (from over active gobies) pretty easily and are none the worse for wear. What you do have to watch is that they are not too close to other corals. They have quite a powerful sting.