400 Watt 20000K Metal Halide Bulb - German Radium, Mogul Base Metal halide lamps of the same kind are different colors?B&gt;Metal halide lamps operate by passing an The metal halide lamp fires and then either burns dull or the arc extinguishes?B&gt;Usually the ballast Do I need a cover shield between the lamp and the aquarium?B&gt;Metal halide lamps produce a large amou Can I operate a ballast and lamp together which are designed for different wattages?B&gt;Each wattage l