Zoo Med Reef Sun 50/50 Compact Fluorescent Bulb, 10 Watts 10 watt, 5 inch mini compact fluorescent bulb Self ballasted compact fluorescent fish tank lamp Fits most standard medium base aquarium lamp fixtures Emits a 50/50 combination of 6500K trichromatic daylight phosphor and actinic 420 phosphor in the same lamp Reef Sun bulbs are ideal for use in marine reef tanks, nano tanks, and aquariums where a "subdued" light effect is desired