I use a cheap DIY home depot 6500k. It works better then my my old compact fluorescent fixture. I just rip some off and feed it to my tangs so it dosn't over grow.
I give mine away to other reefers in need~only cost me $5.50 to ship it. Other wise I get credit from our LFS for it. It doesn't stay there long
i just got one of those light fixtures from tractor supply that they use for putting over baby chicken bucket things to keep them warm and put a bulb in it, wrks great all in all about $8... lol