LED Light Color for Planted Tanks

With Color temperature (K) falling out of the running and RGB taking over, people are now asking what an ideal light spectrum is for their aquarium. With products like the Current USA satellite Freshwater LED plus and Finnex MonsterRay RGB series becoming extremely popular in the freshwater aquatic world, the choices for lighting your aquarium are abundant!

Light vs. Algae

So is there a special LED color ratio that will deter algae blooms? I would have to say no. I have found that various kinds of algae can adjust to varying conditions and flourish in any kind of light wavelength. While plants only can absorb the red and blue parts of the color spectrum, algae includes types of light-absorbing pigments apart from green chlorophyll. Algae has been classified with being different colors because of their light-absorbing pigments, and algae normally use pigments which are ideal for their environment.

For example, red-colored algae consists of a pigment known as phycoerythrin, which soaks up blue light and helps make the algae appear red in hue. The red algae develops deep within the sea. Since blue light wavelengths travel much deeper within the ocean than other colors, this pigment helps the algae absorb light most effectively.

Color Settings

red algae phycoerythrin color light wavelengths in the ocean - redcherryshrimp  LED Light Color for Planted Tanks red algae phycoerythrin color light wavelengths in the ocean redcherryshrimp

So what is the best color settings for your LED lighting to promote planted growth? With the graph to the left, you can see that chlorophyll absorption is highest in the blues and reds. If you have an RGB light like the Current USA Satellite Freshwater LED plus, your best bet is to create a full purple spectrum with white LEDs at maximum.

Green plants typically absorb around the 400-450nm and 650-675nm range, which is the blue and red color spectrum. The red light is used mainly for strong stems and flowering, whereas blue light is used for growing leaves and promoting bushy and compact growth.

Your Viewing Pleasure

At the end of the day, an aquarium is for your viewing pleasure. With setting up your own color spectrum in your aquarium, it’s definitely ideal to try to incorporate the blue and red wavelengths into your lighting with minimal greens/yellows. Will this increase your plant growth exponentially? No, you probably won’t even notice a difference, but it can minimize algae blooms and promote better plant growth.