What Is the Difference Between Blue Light & White Light for a Saltwater Tank?

It̵7;s important to consider the type of light you̵7;re going to use to illuminate your aquarium ahead of time. Aquarium lights can be white or blue, but color isn̵7;t the only difference in these two types of lighting. Having the right light in your tank will not only make it look good, but allow its residents to flourish.
  1. Light Spectrum

    • If you̵7;ve ever seen a rainbow, you know visible light is made of seven different colors: red, orange, yellow, green, blue, indigo and violet. The wavelength determines the color of the light. Blue light has shorter wavelengths, red light has longer wavelengths. Full-spectrum or white light provides light from the full visible spectrum. Blue, or actinic light, emits light only in the blue end of the spectrum.

    White Light

    • Full-spectrum lights or white lights are excellent for making everything in your tank easy to see. Since they contain all visible light, they are good mimics of sunlight. For many plants and corals, light from the longer end of the spectrum is vital for photosynthesis. If your saltwater tank has fish only, this type of light is good for making the tank easy to see and enhancing color.

    Blue Light

    • Since the short wavelengths of blue light are faster than other wavelengths, blue light travels deeper into water than other wavelengths. Corals native to deeper waters will need more blue light for their photosynthesis. Blue lights are good for simulating dusk and dawn in your tank, creating conditions more like the ocean. Blue light alone in a tank isn̵7;t ideal for viewing, since the tank will look dark.

    Lighting Your Tank

    • Before spending what can be big bucks on a light for your tank, learn the light requirements for the different creatures you plan to stock in your tank. Too much or too little of the wrong color of light can be deadly for corals. Lights that produce half white light and half blue light, called 50/50 bulbs, are a safe bet for most tanks.