I have a 400 watt metal halide ballast that a friend gave me, it looks to be brand new. It is a Magnetek 400 watt - part # M400MLTAC4M. It says to use a M-59 or H-33 bulb.

I don't know really anything about MH, My question is that will this work for aquarium light? or is this something totally different?

I think it is too big for my 55 tall, but it might be somthing I can trade down for a 250 set up. Any help would be great.

Thanks Daniel