I am by no means an expert so take my input as JME. I believe the #1 issue, even above lighting and water quality is patience. I bought a few frags (tenius, purple pillow, etc) which looked gorgeous in the tank I took them from - brought them home - all but one immediately turned brown and over the next few days the pruple pillow turned pale (almost as if it had bleached out). I contacted the seller of the frag and she said as long as it has high light (150w in my tank) and hi flow it will be ok - leave it alone and be patient.
I took her advise and around 4 weeks later the corals are now regaining their color very well. It appears that sometimes the corals get shocked from one system to another and need to adjust to their new environment. Good luck with this.