Brain coral skeleton + vacation feeding

[purestar]

I've had this brain for three weeks and just noticed that a bit of the skeleton underneath the flesh is showing. Should I be adding extra calcium or other forms of supplementation in addition to my water changes (with Instant Ocean, every two weeks)? I have a bit of other LPS in my small tank--acan, frogspawn, small hammer and torch.

On another note, I have been feeding the acan and brain every other day or so with mysis... will they be okay without feeding when I'm away for 2 weeks?

Thank you!