cabbage leather coral

Hi All, Have a green cabbage leather in my tank that has been doing pretty well for the past few months. Went on vacation for a week and came back to a small rock laying on top of it, which a fish must've knocked over, ( I blame my bull in a China Shop Blenny). I removed the rock, and it...

Can someone tell me what this is? It’s gotten bigger with a second spot appearing next to it.

Can cabbage coral be kept on the substrate? Will the tissue be irritated? I rarely see any sand covering it and it seems happy but for the bottom half touching the sand. It never seems to as fully extend. Should I prop the rock it’s on up off the sand?

This is my leather cabbage coral I got yesterday, this little guy is my first coral, along with two green striped mushroom coral. I'm so happy, it looks so much better than it did yesterday when I got it.

Have you ever had something grow in your tank where you least expected it to? The is a piece of caulerpa that decided it was going to grow THROUGH a cabbage coral.

The current setup is a 75G tank with a corner overflow with a wet dry sump modified for a refugium area. Eshops skimmer, gyre pumps and Aqueon return pump. Current tank stock includes Tomini Tang, 2 damsels, 3 oscellaris clownfish, serpent starts, Harlequin Basslet, soft corals and mini carpet...

Hi Experts, occasianally I notice a layer of shiny film forming on the coral, is this something normal? Thanks. Sorry it is not very clear in the pics.