Again, a lot will depend on the quality of the fixture, the degree of the optics and the orientation of the bulbs/dimensions of heat sink. used but somewhere around 24 3W bulbs. To give you an idea, a single Aqua Illumination Sol unit would light your tank just fine but so would 2 AI Sol nanos. Likewise, a single 24" Ecoxotic Panorama Pro fixture (~1 W LEDs) would work if you were going for less light demanding corals. Although I have seen this fixture grow acropora quite well. Rapid LED is where many people buy their DIY kits.
