430watt hps bulbs on a 400 watt ballast....

[iGrow27]

I've read a 430 Watt bulb in a 400 watt ballast will only give you the equivalent of running a 400 watt bulb. Save your money. I should note they also say it won't adversely affect the life of the 430 Watt bulb. e.g. a 600 watt ballast with a 400 watt bulb will have shortened bulb life.