Jan,
A good practice I learned was when you get a new frag, place it on the bottom of the tank directly on the sand. This allows the new frag to get used to the new lights it will be living under, then after about two weeks maybe three I raise it up a few inches along the rock wall letting it get used to lights. I have had corals in the past turn brown due to a sudden color intensity change. But if you leave it in the same spot it will or should gain its color back. If you really need help you can always drop it off at my house and pick up your frag which I might have to frag it out. LOL