AquaScience 15000K Special Using a 5 band Phosphorous design Aquascience 15000K SPECIAL From Aquaperfekt will produce an extremely bright 15000 Kelvin, Blue/White light that will remain stable at that temperature until the end of bulb's Life. Because of extreme light output at a perfect color temperature, this bulb is the preferred choice for more light demanding species such as SPS corals. Supplement with Aquascience Blue or Aquascience Special to reach your preferred spectra. Long Life, High output & Dimmable without the flickering effect.