will on e metal halide( mogul) light up a 36'' long tank?

[aqua5]

will one MH light the whole tank up if placed around 8-10'' up in the middle of the tank?does the 175 watt or 250 watt MH give off more heat?will a 250 be able to keep sps color better but not burn lps and softies?

[SunnyX]

The rule is one MH will light up a 2x2 area.
I would go with the 250watt MH.
You can use one MH by positioning your corals accordingly.
Place the most light demanding corals directly under the MH and the softies on the outer rim.

What are your dimensions on the tank?

[aqua5]

36'' long 18'' wide 16'' high

[TheMcs]

I have a 36" 58 gal. My actinics are out so the MH is the only thing lighting the tank (175w 14,000K). Right side is too dark for my taste and there is some shading to the left. I'd do 2 if possible, if not supplement with some tubes.