OK... I'm getting confused now!
One thing I forgot to mention is that I have only had the coral life lights for about two months. Before that, the zoas were under a fluorescent light that was a coral light, that was blue.
What exactly has changed? Are you saying you were running 2x blue tubes before, and now you're running 1x white and 1x blue? Or are you saying that you got a completely new light fixture 2 months ago?
How many Watts do you have now, versus 6 months ago?
Regarding nitrates... water changes are your friend. Do water changes to get the nitrates down and then figure out where they're coming from. Probably that Mircrovert stuff I mentioned earlier.