Today's lighting technology for reef aquariums take advantage of the spectrum and intensity required to keep healthy corals and stimulate growth. The new power compact and T5 fluorescent bulbs have become more efficient than the standard and VHO(Very High Output) fluorescent bulbs and tend to produce less heat than the metal halide bulbs. The best benefit of the T5 lamps is that they are much cheaper to replace than power compact and metal halide bulbs.