Your eyes perceived brightness of that 400 watt light does'nt matter..the majority of the light being produced is NOT in the PAR range..that plants actually use to power photosynthesis.

Buy a 400 watt Eye Hortilux Super HPS bulb and you will be just fine as it's got very signifigant output in the PAR range compared to many other lights, plus they are damn good bulbs and people I know swear by them for final yield. :thumbsup:

Better yet, get a 600 HPS next time...most efficient HID bulb there is lumen/par wise per watt burned and does'nt really use that much more juice.
FreeDaHerb Reviewed by FreeDaHerb on . 430watt hps bulbs on a 400 watt ballast.... Im currently running a 400watt lumatek digital ballast with the stock bulb it comes with and it seems pretty weak. kinda looking to upgrade. I was told by the lady at the hydro store that you can run a 430 watt bulb on a 400 watt ballast with no negative/adverse side effects. Is this true?? :hippy: Rating: 5