The Aqualine T5 Reef Blue lamp is designed for use in saltwater aquariums, emitting almost exclusively blue light in the spectrum between 400 nanometers and 500 nanometers, with a peak at 420 nanometers. These wavelengths promote the growth of many types of corals. Additionally, when combined with a Reef White 10K or 15K lamp, it gives the aquarium a very natural appearance.