I've had this leather coral in my tank for about 6 weeks now. It has started to grow nicely. I just noticed that there is a grey area appearing on the tips of the body in a few places. The polyps are still extending normally and it's appearance otherwise has not changed. I'm not sure if this is normal, i.e. if it is just shedding, or if it's a problem. My parameters are in order except my nitrates and phosphates. They are very high, but that has not affected the other corals or fish. Right now there is just soft coral in the tank, because my nitrates and phosphates are sky high and they are doing fine. Just some zoas, ricordia and Kenya Tree. Here's a pic. Please let me know what you think it may be.