# Beam Angle and Height of LED Light



## christinamac910 (Jan 15, 2016)

So I'm trying to figure out the best height to position my LED light above my planted aquarium. I'm not sure how to do the math to figure it out, and I have had no luck in my searching online. I'd appreciate any help or explanations you all may have.

I have two lights to choose from, the *Finnex Stingray LED Clip Light* or the *Finnex Stingray 10" LED Light*.

I have a small bow-front aquarium. The max width is about 7 inches. The height from the lowest part of the gravel to the top of the aquarium is about 6 inches. The height of the glass itself is about 7.75 inches. The length of the LED fixture is about 9.5 inches, with the bulbs only spanning 8.5 inches.

How high above my aquarium should I position my LED light? How would I go about calculating this? I know beam angle is important as well, but I don't know how to measure this.


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## Michael (Jul 20, 2010)

I have two Stingrays above my 40 gallon breeder Walstad tank. I needed two because the beam angle of the Stingray is relatively narrow, and the 40 is 18" wide. My Stingrays are mounted with the standard mounting legs that come with the fixture.

Given the size of your tank, I think you can use the standard mounting legs and get good coverage. The only reason you may want to raise the fixture is if you plan on a low to medium light tank. Using the mounting legs may give you too much light.

Not many people use the Stingray on planted tanks, and I don't usually recommend them because of the narrow beam angle and relatively low light output. But for narrow, shallow tanks like yours, I think it will work well. And it is a great looking fixture!


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## christinamac910 (Jan 15, 2016)

Thank you for your reply, Michael.

I am aiming for a low to medium light, "low tech" setup. I agree that the beam angle seems slightly narrow. If I had to guess, I would say it is about 145 degrees. With the 10" Stingray centered on my aquarium with its mounting legs, I felt that some of the plants in the back were not receiving enough light. This is why I started considering how I can position the light higher and what the proper height would be.

I recently moved my HOB filter to one of the short walls of my tank near the front glass, and there is only room for me to position the light with its mounting brackets at the very back of my aquarium. This is why I purchased the clip-on version of the Stingray--so that I could center the light and easily adjust the height.

I have the Stingray Clip Light set up right now (2.75" above aquarium rim), and I am noticing that there is a lot more light spilling onto my desk since the clip light is positioned higher than the other Stingray on its brackets (about 1" above aquarium rim). I have heard that light spilling through like this means that the light could be positioned too high? What do you think?

Are there some key things I should pay attention to that will let me know what the best height would be?

Thank you again for your input and advice.


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