Lighting HPS dimmable ballast question..

[fweedom]

hey guys right now i have a 400w hps that i can run at 50%, 75%, 100%.
ive always run in at 100%.

im thinking of getting another tent and the same 400w HPS with a dimmable ballast.

My question is if i run it at 75% is it then using up 300w AND giving off only 75% of the lumens then originaly?

the 400w hps bulb box says 53,000 lumens.

So if i run the ballast on 50% im only getting 26,000 lumens?

or at 75% im only getting 39,750 lumens?

im thinking of dimming one to use up a little less wattage but i just wanna make sure i understand and that im calculating it right before i start ordering

thanks guys

 

[Baldy]

You can use any dimmable ballest you want. I have a 1000watt dimmable turned down to 850watt in a 4X4 tent for my REGULAR strains, not sure about any auto flowers. It seems I can't find ANY info on WHAT TYPE of light to use. Any help here would be great. By the way, I get billed .23 cents (US dollars) per kilowat used and I use around 1,500 a month for the entire household including the HPS lights, fans, CFL, T5 and what have you. However any help on WHAT TYPE of light to use would be a great help, thanks.