Bad Idea?? Switching Bulbs For Desired Results

[cham]

I am thinking about buying two XM 10,000k bulbs for my mixed reef to promote growth. I have two barely used 20,000k laying around.

I was thinking of running the 10k for several months to promote fast growth and then switching to the 20k once I was happy with growth to color them up.

Will that work like that? Anything to watch out for?

Thanks