MH and HPS for flowers

Hey guys I have been lurking for a while now and I can't seem to find an answer to this by searching. I have had a 400 HPS and 400 MH fall in my lap recently. I was planning on using a 600 hps for my flowers but I have not bought it yet.
The question is, could I use both at the same time for flowers? heat will not be an issue. I know more light is better but I am worried about the MH over powering the effects of the HPS.
be easy I'm new

the light spectrum will be there for the plant to use if its not wanting or needing it, it wont use it fire them both up...rob

as long as heat is no problem, you can definitely use both. they each put out a different spectrum and won't "interfere" with each other. not sure how you're planning on placing light - that could be an issue. may have to shuffle the plants around under the lights.

the light placement is something I have been pondering, I am thinking either both of them right next to each other in the center OR the HPS up high and the MH on a stand to use as side lighting. This would mean I have to move the light around everyday. <shrug>
If anyone has a good idea on how to set up the lights I am all ears.
some specs:
10 plants vegged for 5 wks
4x4x6 space
3.5 gallon buckets

thanks for the fast answer guys.

USE BOTH! the more the better, but with heavy lighting, heat is your worst enemy. get a digi thermometer. they rip

I am using this idea to got the idea from JIGFRESH when he used it and the harvest was amazing.

I had two lights already and just cut them up and put them together with diy cooltubes, does not look the best but it should work( was looking for a nice enclosed light reflector that holds two lights i saw one before) , after fighting the temps for a long time i fan get the room to stay under 82 (using co2)and the cooltubes are cool to the touch ........

if you have a grow going cerberus put up a link i would like to fallow it.

Use them both. You can use either one from start to finish or both. You will be fine. Ideally you want to veg MH and flower HPS. The theory being that the red and orange spectrum change represents the light that gets through the atmosphere during the fall and winter months when we are tilted farther from the sun. The reds help to trigger the hormonal changes in the plant to flower but it is not the main reason plants are triggered to flower.