Poci's. Pocillipora damicornis---it's a fast grower, and very tough, lower light, about like a frogspawn: they repair their own dings. The montiporas are very forgivingb, and after them, I'd put ac. valida, which isn't a fast grower. Oh---and ac. yongei---the green bali slimer, which is a great learner's sps: it will slime if annoyed, so you know where you stand with that one; but it likes light. I enjoy a mix of the sps/lps, because sps don't change too fast...Sps're going to like metal halide best: I use a 250 in a 52 gallon corner. You may be able to get by with less, but the coloration may not be all you could wish with anything other than mh. I did use the actinic/high output fluorescent once, for about 5 years, but I can't say we ever kept sps. It was barely adequate for lps, and we did fine with some of those. Sps was not a possibility in those dinosaur days. Good luck with the notion---I enjoy mine, no question.