If you just got it and are keeping it that high in the tank, I would say that is your issue. Your other corals look okay so the parameters should be fine. I like to leave corals in the Lowe 1/3 of my tank for up to 2 weeks to adjust. I'd really recommend moving him down and leaving him alone for 2 weeks.
I suppose I'm just concerned with adding too much in my 5gal. The red sea salt coral pro that I'm using is already pretty high in calcium. What are the draw backs to 465-550 ppm? Having too much that is.
When calcium levels getting high (475- 500), there is a tendency for alkalinity to drop, affecting the buffering capacity of your tank water.Without adequate buffering, pH levels become susceptible to fluctuations.