600w H.I.D. Adjustable ballast Capable of using a 400w Bulb?

I was wondering if a 400w Hps would be good to go using a 600w adjustable H.I.D. ballast on the 400w setting? Anyone have experience with using lesser watt bulbs and turning the adjustment down on higher rated ballasts? Considering the bulb base is the same. With my electrical knowledge the only thing I can see that may be an issue is the inrush may not be there to excite the bulb.
I plan on getting a 600w or 1000w ballast and hopefully may be able to use a few of the 400w M.H. and HPS bulbs I have on reserve for my original 400w fixture to use in the begining phases of some grows that do not require the high wattage at first.
Thank you for those who have an input.

I believe I’ve seen this discussed here before, and the bulb has to match the ballast.


It will burn the bulb out quickly.

1 Like

The others are correct. You need to size the bulb to ballast at full power.

I would get hey a galaxy ballast mine does 400w 600w and turbo 600w