I have the Reeflux 12K 250W DE's on Icecap ballasts. They are white. I run them with 2xT-5 Actinic and the color of the tank is crisp white with a hint of blue. Coral growth has been very good and corals are changing colors from brown to blues or greens. All of the other corals either have a deeper blue/purple or have lightened up with good intensity.
I run 175w reeflux 12k and Let me tell you i love the color ,and even ppl that come here love the color of it ,even if they dont like reeflux bulbs ,I had the 10ks but they where too white for me