Metal Halide

[barristan]

I am currently running with 5 overdriven NO bulbs, (4 of them at 3X and 1 at 4X). I decided to do this because I was afraid of the heat issues and the initial cost of a metal halide setup. But now I am thinking that I want to go the MH route.
The only corals I have now are an Alveopora and a Sebae Anemone(for now).
My tank is a 55 gallon. I was thinking of adding only one MH in the center, maybe a 400w or a 250w. Would this require significant cooling? would this be enough light?
To tell you the truth I think the setup I have now looks as bright or brighter than most of the pics of MH setups (http://www.coralreefecosystems.com/ltg_bulb_color.htm)that I have seen.
But I think I want to do it anyway. Opinions appreciated. Thanks.

[MalHavoc]

The main problem with a single bulb over what I imagine is a 4 foot long tank is that a MH bulb typically only covers a two foot area of your tank. If you put one over the middle of your tank, the ends of the tank would be significantly dimmer than the middle.

That can work to your advantage, if you don't mind putting stuff that does not require intense light at each end of the tank.

I don't think a single MH bulb will cause you heat problems.