Blues are best brought out with white light, and most of the time turn to green when stressed from a list of issues. Most blue corals take a good while to come back to being blue after changing color like that too. I agree with the blue led issue too. Also there are not too many truly blue corals around, a lot of them are more purple than blue. I would say the best way to keep good blues is to keep a good spectrum and sea water nutrients.
I don't really like the idea people get when they say jason fox uses all blue light either. He is getting white spectrum from his t5s even though they are blue t5s. Big difference from using just blue led. And Jason picks his corals for certain reasons, because he can sell them and make them look really cool under blue light. I bet he has a long list of corals he stays away from because they don't do well or color up in his tank, most people do really. But if you look at a lot of the guys in europe who use a lot of white light they are keeping corals that are much harder to color and grow with tons of success. In the states not many people have success with them.
