GE makes 6000k colour temperature 20W's. They're usually about $10USD in american stores, better than the $20-30 each i've seen the coralife ones for sale here.
I'm also thinking just forking out the money for a teklight retro kit would be worth it. Go 2 bulbs over a 48"Lx10"Hx12"W tank. Would be enough for most things, and I could get another one later. I know it'd be higher quality than the dairy-queen bulbs and more reliable. And more versatile in case I decide on doing something else with the lights later. Those workhorse ballasts are pretty universal.
It'd be about $190 with bulbs if I went T5. Better than $15-20 each for the dairy queen ones, and probably needing at least 5 bulbs. That's at least $100 there for the cheap ones, not including sockets and wiring.
I think 2 bulbs over a 12" wide water surface would be fine in an 8" tank with a water depth of like 7.5"
It's funny. I've got 2 reef tanks going now. Only ~5 days after the 2nd one's running, and I'm already planning on another. I'm going end up with a fishroom before everyone else in the house realizes it's too late
