NOOOO

no on that, no on the 400 into a 1kw ballast... NOOO non matching bulb/ballasts!

the bulb / ballast wattage MUST match... sure, the light may WORK in a different ballast, but over an extended period of time that growing requires, there is a good chance that, at the least, the bulb will crack or explode, and at the worst, will cause a fire... if you have made it through a whole grow with mismatched bulb/ballast wattages, then you were very lucky IMO

spend the extra few bones to get the proper bulb, and sleep better at night :twocents: