About the Marine VHO Actinic Fluorescent Lamp The Marine VHO Actinic Fluorescent lamp is a 100% blue actinic 03 phosphor which peaks at 420 nanometers. Lighting with a higher blue component better simulates the softer more subtle shades of dusk dawn and the blue hue of deeper water. The wavelength of blue light has the ability to deeply penetrate water providing your fish with adequate light. Very high light output makes this lamp perfect for larger aquariums