In general they like lower light and flow, and light acclimation is key when adding new specimens to the tank. I had one that I thought died completely and put the "skeleton" in a shaded area and it grew back completely. I've read many places that they like magnesium a whole lot and if you maintain a slightly higher magnesium level that you'll get better growth out of them, that in conjunction with keeping your calcium and alkalinity where they need to be. What kind of lights are you running? You may need to shade new additions even if they are already on the bottom of the tank. They also like "dirtier" water, I've seen several that declined slowly in low nutirient sps tanks. And, from my experience, freshly cut chalices absolutely HATE my tank and several freshly cut chalices including a rainbow crush that still breaks my heart that it died have perished in my tank when they were fresh cuts. If you're getting frags make sure they're already healed and have an established growth ring