As far as the calcium I don't have any problems with it. The colt is a soft coral so I don't think it uses calcium. I add b-ionic daily.
The yellow stuff on the right is actually a green star polyp. It just looks yellow because my camera sucks. It's really a beautiful floresent green and I've moved it from the left side of the tank to that spot and left some behind on the left were it has grown back real well. I also pull some off the big piece every few weeks and glue it to a new shell and put it in my prop tank to swap.