Using Less Wattage for HPS

I was wondering if you could use like a 250 watt bulb on a 400 watt HPS ballast.

And if you do, does the ballast only use 250 watts of power, or will it still suck up 400 watts of power and use the remaining 150 watts of extra power as heat production?

thanks.

i was thinking about jus gettig the highest wattage ballast i can find and just alternating wattage to fit my electricity bills. Because a 400 hps ballast is like 30 dollars more expensive than a 150 watter. So it'd seem better idea to jus get the 400 and use a lesser watt bulb if it was the same

I'm interested in the answer to this too, as I'm thinking of putting a 250w HPS bulb in my 400w ablite lo-bay.

A 250w MH bulb is currently in this 400w ablite lo-bay with inbuilt ballast is working fine but would this be the same for 250w HPS bulbs too?

idk. i konw that Mh ballast and HPS ballasts are similar though, so it might work. But i'm more interested in how much wattage it will use. If it's going to use 400 watts to power a 250 watt bulb, and have the extra 150 go to waste as heat, then i might as well jus use a 400 watt bulb.

should work just fine depending on if its digital ballast or magnetic. digital ballasts are made so that you can upgrade, for example say you buy a 600 watt digital hps ballast. it will power any wattage of hps bulbs up to the 600 watts. so 150w 250w 400w

I have a built-in magnetic ballast in my 250w MH Lobay light fixture (my mistake on my earlier post where I said my 250w MH works fine in my 400w Lobay, its actually a 250w MH Lobay). Will a 250w HPS work on this 250w MH ballast??