Supplemental lighting for 250W MH on 24" cube?

[ScubaSteve]

A 250W over that tank could keep anything (this is the same set up I have). If you want better colour rendition, a 14K Phoenix bulb or a 20K bulb would do wonders (if you're using SE bulbs you could use the super awesome Radium 20K). My fixture also uses 4x24W KZ Superblue T5s for supplement (though these alone can grow almost anything in the tank) and it's an awesome mix.

What fixture are you using?

If you're handy you could also whip up a fairly cheap LED supplement.