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What Is The Best Light Spectrum For Coral Growth And Coloration?

by Brian Dunleavy
What Is The Best Light Spectrum For Coral Growth And Coloration?

One of the best things about a saltwater reef aquarium is the ability to create awesome colorful displays. From the brightest Homewrecker Coral to the vibrant Space Chaos Zoanthids, getting the best lighting spectrum will make your corals' colours burst!

Lighting is the most important factor for coral growth. Knowing the different light spectrums, and which one is best for your coral to grow inside your aquarium, will make your reef aquarium more colorful.

Some light spectrums are better than others at enhancing specific coral colors, so we have picked out the different color spectrums for coral growth, and which PAR level is best for corals. 

Lighting & Coral Growth

Most corals kept in your aquarium are likely to be photosynthetic, which means they rely on aquarium lighting for some of their energy needs.

It is the specialized symbiotic algae called zooxanthellae that can utilize this light to produce sugar for energy and then transfer it to your coral’s polyps so that they can successfully grow. 

In return, your coral provides the zooxanthellae with a safe home and a constant supply of carbon dioxide for photosynthesis. Photosynthesis not only needs the right amount of PAR, but the process also requires the correct light spectrum. 

What Type Of Color Spectrum Do Corals Need?

The blue spectrum is what is needed for coral growth. Blue wavelengths stimulate coral reef calcification, so if you have stony corals inside your aquarium, blue lighting is extremely important. 

According to studies, blue lighting results in higher coral growth and zooxanthellae density. Lighting with a high blue spectrum is extremely popular, as it can also boost your coral’s pigmentation and production of chromoproteins.

Color Spectrums For Coral Growth

In the wild, light penetrates the water at different depths. As depth increases, reds, oranges, and yellows are filtered out, leaving the blue spectrum. This is why the ocean appears blue, and why you need to use a red or orange filter on your camera when taking photos and videos underwater. 

For optimal coral growth, you want a full spectrum of light, including a heavy blue range, but also some reds, oranges, and yellows thrown in there too. 

Now, you have probably noticed the current trend in the hobby towards very blue reef aquariums with brightly glowing corals. While we agree this type of display is fantastic, it is still important to provide a full spectrum of light for your corals to grow. 

If you do opt for the very blue actinic lighting, we advise you run a fuller spectrum first, so that your corals can transition and acclimate to bluer light spectrums over some time.

Reef Spectrum

If you have an epic zoanthid garden inside your reef aquarium or have a large display of other soft polyp corals like Leather Corals or Xenia, a reef spectrum is perfect. 

A reef spectrum provides purple light, which enhances green, yellow, and orange colors inside your aquarium. The mixture of blue and red hues also creates a visually relaxing feel, and with the high blue lighting, your corals will grow very well. 

Spectrum Range: 

  • Blue: 75 - 100%
  • White: 0 - 10%
  • Red: 75 - 100%
  • Green: 0%

Full Spectrum (10,000K White)

For shallow reef corals (like Acropora) , an intense white color spectrum will mimic their natural environment. By combining a high ratio of blue and white, this lighting spectrum not only provides your aquarium with a very natural look, but is perfect for coral growth. 

Aquariums with a full light spectrum and crisp white lighting also create a stunning shimmering effect when the light bounces off fish and live rock. If you have a fish-only aquarium, you can also use a full spectrum, but you should lower the intensity as it can cause excessive algae growth. 

Spectrum Range: 

  • Blue: 85 - 100%
  • White: 80 - 100%
  • Red: 20 - 65%
  • Green: 20 - 65%

AquaBlue+ Spectrum

AquaBlue Plus spectrums focus on high blue intensity and they are the typical ‘go-to’ light spectrum for reef aquariums. This light spectrum is one of the best because it has been proven to successfully grow corals very well and show off vibrant colors in both nano tanks and larger aquariums. 

Spectrum Range: 

  • Blue: 85 - 100%
  • White: 15 - 30%
  • Red: 10 - 20%
  • Green: 5 - 15%

Actinic Blue Spectrum (14,000K)

14K actinic blue lighting is one of the most popular choices for diverse marine tanks. Their stunning color temperature creates an impressive, vibrant display for both fish and corals. 

The very subtle white spectrum will give your aquarium enough shimmer without causing issues with excessive algae growth, yet enough blue and white light for optimal coral growth. 

Spectrum Range: 

  • Blue: 85 - 100%
  • White: 10 - 20%
  • Red: 25 - 60%
  • Green: 5 - 20%

Super Actinic Royal Blue Spectrum 

This is the only light spectrum that only consists of blue wavelengths. The pure blue spectrum increases coral fluorescence and promotes healthy coral growth. We recommend only using this spectrum if you are an experienced hobbyist, as blue light can be harmful to fish if used incorrectly. 

Spectrum Range: 

  • Blue: 75 - 100%
  • White: 0%
  • Red: 0%
  • Green: 0%

How Much PAR Do Corals Need?

Photosynthetic Available Radiation, or PAR, is the amount of light that is in the proper light spectrum for corals to utilize. Depending on which coral you have, will determine which PAR level your aquarium lighting should be. 

Below are the typical PAR levels:

  • Soft Corals: 50 - 150 PAR
  • Hard Corals (SPS & some LPS corals): 200 - 500 PAR
  • LPS Corals: 50 - 150 PAR

  • I know what you may be thinking… ‘What happens if I want to have a mixture of different corals inside my aquarium?’ The good news is, most corals are forgiving and can adapt to a wide range of PAR levels when acclimated over time. 


    For optimal coral growth, typically a full spectrum of light is best. This means lighting that focuses on the blue range but also includes some reds, oranges, and yellows. Blue lighting is becoming increasingly popular for reef aquariums, creating the perfect glowing display.

    If you are unsure which lighting will be best for your aquarium, or are looking for new lighting fixtures, do not hesitate to contact the Reefco team, we are always happy to help with any aspect of your aquarium!

    by Brian Dunleavy