Also...
my favorite corals are zoanthids. I find that some open up almost as soon as I put them in the tank, every polyp. But some take a week for even a single polyp to open. Besides light they take a while to adjust to the water conditions of the tank. So far the only ones I've killed were the ones I put 4 inches under my 300w of VHO right after bringing them home on the old tank. They cooked in a day! And those came from a store that had them high up under a MH. I also bleached an acro under those same VHO's. I saved him in time though and he recovered.