The Aqualine 20000 lamp has a color temperature of about 20000° Kelvin. The use of this "actinic" bulb enhances the flourescent blue and green colors of many corals. The bulb should be used in combination with Aqualine 10000. This combination gives the aquarium a beautiful bluish hue. Many corals show positive reactions if illuminated with aqualine 20000 and increase their growth rates.  HQI double ended lamp.