# Led question



## aquariumrookie (Jun 26, 2014)

Hey guys i bought this waterproof led adhesive light strip that said it was 6500k in hopes of being able to grow plants. When i set it all up, the aquarium looked kind of blue not a deep blue but a whitish blue. Will this grow plants?
I usually use cfls, but this time i bought a 10 gallon aquarium kit with a shallow hood and it already came with some crappy leds so i just chose to buy some cheap adhesive leds this time to just experiment.
Do you guys think it will grow plants?
THANKS!


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## Gilby (Feb 15, 2014)

It'll grow some plants. The intensity of the light (PAR) is going to determine what plants you will be able to grow. Only a PAR meter will really tell you what that intensity is. You could however guestimate it if your lights have a lumen rating, and failing that, go by watts.


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## TropTrea (Jan 10, 2014)

It would be nice if we had more information on this particular LED. 

Basically a 6,500K light source will work for aquatic plants if it is bright enough. Lighting can be simply divided into three ranges blue, green, and red. An equal combination of the three produces what we see as white light. The Blue and Red light is what the plants need for photosynthesis. The green light is the light that the human eye is most sensitive to but does little for plants.

As you go through the K scale of light you find that true 6,500K lighting is stronger on the blue end of the spectrum than on the red end of the spectrum. If you go to higher K levels the Blue portion increases even more. When you get below 5,000K the red end of the spectrum starts to be more dominant. 

Many individuals mix different color temperature or even colors of LED's to get the best growth for particular plants. Also keep in mind that just because someone says a light is a set K rating does not always make it as ideal as another light source at the same color temperature as specific wave lengths that are being generated may be different. 

If this light is intense enough for the plants your trying to grow then it should not be a problem. but a perfectly tuned light source for plants can grow plants with only a fraction of the total power needed from a poorly tuned light source which has a majority of the light in the green part of the spectrum.


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## Tugg (Jul 28, 2013)

There is a REALLY good presentation from MACNA 2014 about LEDs and lighting in general. At about 11 minutes in, it gets into color spectrum.


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## TropTrea (Jan 10, 2014)

Tugg said:


> There is a REALLY good presentation from MACNA 2014 about LEDs and lighting in general. At about 11 minutes in, it gets into color spectrum.


This is a good explanation however it is based on reef tanks. With Fresh water plants more red light is needed than in Coral tanks. I had done some comparisons myself with corals and will say that best combo I used for coral growth were with 80% of the LED's in the blue range and 20% in the neutral (not cool)white range. Using Cool Whites it would closer to a 66% blue range and a 33% Cool White range. But using something like this on a Fresh water planted tank yields loads of algea and poor to fair plant growth. Plants need that RED light which some corals hate.


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