it's deep water I think. Low par (bottom of the tank/at sandbed) and has to be temps of 75F to acclimate for a while. It'll bleach at high par but with feeding, it will recover.
@bubbgee is correct. They do require moderate lighting, but try to make it indirect lighting. Meaning, don't place it directly under your lights.
Give this article a read, it has some information I think you will find useful.
Beautiful symphyllia by the way!!