I'll through a little info here from what I know. First off HID stands for High Intensity Discharge and refers to metal halides, halogens, mercury vapor, high pressure sodium and so on. The lights you're referring to are very similar to metal halides but use a slightly different gas.
The main problem with this type of lighting is the spectrum, the lumen output means nothing when it comes to corals. The blue color or higher K rating of the bulbs are created from a coating on the bulb, so the true spectrum isn't where you want it. You'll get better color and efficiency from other types of lighting.
In addition I believe metal halides are a cheaper solution and you won't have much luck finding a good reflector for those bulbs. They have their application but I don't think it's in the aquarium.
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