+1 turbulent flow and occasional feeding. I have 5 gorgonians from sealifinc.net, all photosynthetic. They're under 195 watts of T5 in a 50 gallon with about 2500 gph of flow. A few have grown to within an inch or so from the lights, so they can take a lot of illumination. I made sure to place them in the most turbulent areas of the tank, with one specimen blasted directly by a pump, it's polyps happily extended in the flow. Be sure that you have any algae/cyano under control as they'll grow on your gorgonians and kill them. I used to feed mine oyster feast, and they showed a feeding reaction but it didn't make much difference in their growth so I stopped doing it regularly. Hardiest? Probably sea feathers Pseudopterogorgia and knobby sea rods Eunicea. Purple plumes are hardy too, but will sometimes recede for no reason. I had one seemingly disintegrate only to make a rapid and total recovery in two weeks.