nigel685,
Psammocora spp. corals are pretty common in Fiji and Tonga where they grow in many different habitats from turbid in shore areas, to out on the reef where you normally find Acropora, Seriatopora, and Pocillopora. I do not order Psammocora that often from overseas as the market for this coral is really not all that great. It is however a pretty common hitchhiker on other corals or rock, such was the case with the Zoanthus rock.
Most species of Psammocora are pretty intolerant of very intense lighting, so I would recommend not blasting it with halides. When they are over lit or stressed the coral can turn yellow. For best coloration in your aquarium (they normally turn green when they have settled in and are receiving good flow and moderate lighting) I would place the Zoanthus rock in the shade of other corals or at the bottom of your aquarium and to the sides if you do in fact have intense halide lights. If you run T5's, VHO's or PC's then placement in the middle or the top of the aquarium would be ideal. Like most encrusting hard corals, flow requirements should be moderate to strong indirect current, and the coral should spread pretty quickly as long as your water parameters are stable and correct.
Please let me know if you have any other questions, and I will be more than happy to help.
Sincerely,
Kevin Kohen
Director of LiveAquaria
Drs. Foster and Smith