I've used the 10W and 20W Coralife 50/50 screw-ins. They aren't very bright, but they'll do for numerous low-light softies and LPS. The colour is pretty good, too.
I'm switching over to Philips Marathon Daylight bulbs, though. They're cheaper, brighter, and I've had good success in my planted tank and in my mantis nano tank. The nano tank doesn't have corals in it, but the coraline grows well. I'm putting four of the 27W Daylight bulbs over a 16 gallon display (20" x 15" x 13" H). They look very bright, and I figure my mushrooms and other corals will do well.
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Medical Marijuana