Hello. I am looking at a Metal Halide lighting fixture. It comes with a 250 watt hqi metal halide bulb and 2 x 96 watt power compact bulbs. My tank is a forty six gallon bow, roughly 24 inches high. Would this suffice? It comes with moonlights also. This unit would supply 9.6 watts per gallon. Also, the retailer is giving me the option of 10k, 15k, or 20k. From what I have seen, I prefer the 10k. However, is this not a beneficial to coral? Finally, the unit is selling for $399.99 without shipping.. is this worth it?