why are my hps lights 2 different colors?

There both 1000 Watts.and I noticed 1 is white and other is a yellow color.kinda new to growing.but my buddy gave them to me.can anyone tell me the one I need for flowering.again they are both 1000 Watt hps bulbs but one is white light other is yellowish. I just want to no what one to use flowering.thanks for any help!

sounds like one is an MH and the other hps MH is for veg hps for flower

One may be a MH (metal halide) and one may be a HPS (high pressure sodium).
The MH bulb will be the pure white or slightly blue-ish tinted one.
The HPS will be the yellow tinted bulb.
You should use the MH for veg and the HPS for flower.

But I will say that some HPS bulbs do look allot more white in color then others.
So it may just be two different HPS bulbs.

Some dual spectrums don't look as yellow, if u need to use both lights and oneis MH, u can use both as it will be like dual spectrum, by if u haven't got a light rail maybe every 3 days alternate the bulbs, so each side gets both spectrums.

Youll see some big grow ops that have say 6 HPS and 4 MH for flowering but they would use them either on light rails or alternate which lights come on if they have enough lights.
alternating the Bulbs should work fine.

HPS Yellow=flower
MH white=veg

Thanks for the replies..but on bulbs they say 1000 hps,.and whn I turn them on, one is brite white.the other is like a yellowish /amber color.and where the bulb is where you stick it in(on the end of the bulb)..one is white in color.the other is lite tan.it just threw me off cause of the two different colors of light.when they both say 1000 Watt hps bulb.thanks for the replies!

Hmmmmmm not sure, but HPS should be a yellow color, maybe the other one u have is burnt out , but I am not too sure