lighting question

[rookie50]

I've got a 50G bow front with a 192W Corallife CF fixture 1/2 blue 1/2 white light. Over the last couple months my corals aren't doing well in this tank. I've been blaming the fish since when I move the corals to my 20G they flourish.
But now I'm waundering if the lights are losing their effectiveness. They are about 5 months old but I don't think they are as illuninating as before?Could I replace the blue bulb with another white one?

[tims]

yes you can , the blue is a bit more for us. the whiter the tank the less it looks good for us.what type of bulbs are they again? t5,t8,t12 ?
that is a bit fast for them to burn out, with having a par meter to measure the wavelenght no real way to tell.