I would put my rag tag collection as a minimum if you are going to keep sps coral. If I had the money, I would go with 3 250watt Metal Halides, and 8 36 inch (312 total watts) t5ho's w/ tru actinic. A lot of people used to talk about watts per gallon(minimums being 6-7 watts), but I think there are too many factors these days.