That's what I'm hooking up on a 20g tall, so depth of light penetration will not be an issue for you. My only concern/thought would be (depending on the canopy height) the "focus" of the MH bulb. The intensity would be less on the ends, so some lower light corals may be in order on the ends. In the middle, I would think you could keep just about anything. I personally am using 55w actinics, but I like the blue. It's all a personal preference though.