T5 Aquarium Lighting Colors

The T5 fluorescent bulbs are thinner than the more common T8 bulb size, but produce more light output -- lumens -- than a comparably sized T8 bulb. Considered high output,T5 light bulbs are commonly used in saltwater aquariums where light intensity is required for water penetration. T5 bulbs are available in colors ranging from about 3,000 degrees Kelvin to 10,000 degrees Kelvin. Actinic T5 bulbs, operating at 420 nm in the light spectrum, are also available for reef aquariums. T5 bulbs should be replaced on a yearly basis for optimal light production.

  1. Degrees Kelvin

    • The color, or hue, of a light source is commonly measured in degrees Kelvin. Kelvin temperature, named for the physicist William Kelvin, refers to the spectrum of colors produced by the light. William Kelvin noted as black iron heated, the color progressed from deep reds to bright white. The Kelvin temperature system contains reds at the lower end of the spectrum passes through white, changes to blue at the upper end.

    Color Ranges

    • T5 bulbs with a 3,000 Kelvin rating will have approximately the same color value as the sun at daybreak. This light is visually more yellow than a household light. Bulbs with a 5,000 Kelvin rating will approximate sunlight at noon, with a full spectrum of colors. A color spectrum of 6,500 Kelvin will appear to have the blues commonly associated with an overcast day. A 10,000 Kelvin rating will have very little red or yellow, and will appear as a bright white with a blue tint.

    Actinic Lighting

    • Actinic lighting is a deeper blue than is found in 10,000 Kelvin blubs. Actinic lights are used to approximate the penetration of sunlight in deep water. Actinic lighting is required for reef aquariums to allow corals and other marine life to thrive.

    Mix and Match

    • Many T5 lighting hoods will accommodate multiple bulbs. Mix and match bulb colors to provide a custom spectrum of lighting for your aquarium. Full spectrum lighting will allow your aquarium to reflect yellows and reds brilliant at 3,000 Kelvin as well as brilliant blues so readily seen with 10,000 Kelvin and actinic lighting.