Ceramic metal halide

Hi, guys. So I have a 600watt digital ballast with a dimmer switch. I wanna give cmh a go but they don't make em in 600watts as far as I can tell. So I'm wondering if I could use a 400watt cmh and put the dimmer on 75%. Has anyone tried this?

you need to get a 600 watt metal haloid bulb . don't run a 400 in it.

ok, thnx. NOw that i think about it it would probably just run the 400 at 75% if i it were to work anyway. Guess I'll have to get a 400watt ballast. I don't think i will ever grow that many plants at once were i need 600 watts, even tho i have the space.