Hmm, will it work on a 400w MV ballast? Brian said nop, but he migth of thought it was pulse start. will a MH bulb work with MV? ill takwe a pic of the bulb. its 400w./

says it works only with ANSI M59E ballasts.

MH require higher OCV then MV, so it might not ignite. You might overcome it by adding low voltage pulse ignitor (<1kV; series combination of ~150W 240V incandescent with "higher power" fluorescent starter might work as parallel ignitor).

Yeah, the lower OCV will create starting problems. Also, it's been said that the MV ballasts have a more distorted current waveform and could shorten the life of certain MH's.