The Coralife Actinic 03 Blue lamp is a 100% blue actinic 03 phosphor that peaks at 420 nanometers. The Magtinic is the same lamp with a 180o highly-polished external reflector. Lighting with a higher blue component better simulates the softer shades of dusk dawn and the blue hue of deeper water. Additionally many marine invertebrates depend on blue light the wavelength that most deeply penetrates water.