Correct ... it is the bulbs. My ballasts came from HD before they stopped selling raw ballasts. At $30 per ballast I am VERY sorry they no longer sell them! Although at $30 per ballast I guess I understand WHY they are no longer selling them... they had to be losing a fair bit on that one.
Technically I'm not sure if fish care about colour temperature so much.
Corals might though
:P ... For me, the issues of using <4300K bulbs are twofold: 1) very "yellow" or "green" in appearance, offering no aesthetic value; and 2) promote undesireable algae growth. Spectrum of a bulb of course plays a pretty important role too.