Multiple T5s with quality bulbs for sure, 2-55w PCs with a good reflectors in a shallow tank will work. Keep the water as clear as possible to aid with light penetration. Remember the goal with this approach is for the Xenia to thrive not just survive... I have found it near impossible to burn or over light these corals. The fastest growth I have ever seen was from a 65k iwasaki 400watt M59, with a PPFD of 250+ and guessing par at 700 to 800 for 12hrs a day.