I think that last post could do with some clarification. The live rock itself doesn't require any special lighting at all. The bacterial populations that perform biofiltration, which are the primary reason for having live rock, will do just fine under 30 watts or even in an unlit tank. However, you *will* find that more of the hitchhiking critters that are probably on that rock will survive if you have better lighting. I don't know, myself, if the coralline algae that gives the rock its color requires any particular level of lighting. I believe the coralline in my tank has started getting its color back now that I've got the lights onto a full-length photoperiod, but that's a pretty subjective observation.