LED emitted angle

**amirfield** · 05-18-2012, 02:38 AM

At present, led emitted angle usually is 60, 90 120 optional, most products are 120, but some professional said 90 will be better, I have no idea that 60 90 and 120 which one is prefered?

**amirfield** · 05-18-2012, 02:42 AM

Sorry, just forget to mention: if these leds are used Aquarium reef tank light, so which angle will be best choice, 60, 90 or 120?

**Cliff** · 05-18-2012, 02:55 AM

I've got AI SOL LED lighting on my reef tank with 3 watt LEDs made by Cree. They have a combination of 40 and 70 degree lenses. I would think a combination with be better to concentrate the light under the fixture as well as spreading the light out. I'm really impressed and happy with them as they have a better quality of light as compaired to the other LEDs I had a change to see in operation.

**dbosman** · 05-18-2012, 07:50 PM

Originally Posted by amirfield

At present, led emitted angle usually is 60, 90 120 optional, most products are 120, but some professional said 90 will be better, I have no idea that 60 90 and 120 which one is prefered?

It depends on the height above the substrate, and if you have a fish tank or a planted tank. For planted, you want the "cones" of light to cover the top of the plants. That means you'll have some light spilling out of the tank at the substrate level. For a fish tank, you can narrow the cone of light using optics and keep all the light inside the tank. That leaves some areas near the top unlit, but can make the tank more of a focal point.

Here is a good discussion thread
http://www.plantedtank.net/forums/li...led-light.html

My next purchase of emitters is going to include three sets of optics so I can try them on the same panel and see the difference on my tank.

**Reefing Madness** · 05-18-2012, 11:12 PM

60-80 is usually good. Most don't hang the fixure more than a foot above the water anyways.
And, those are focusing lenses in degrees they are referring to.

**amirfield** · 06-06-2012, 04:17 AM

Thanks for all replys, that sounds from 40-80 will be a good choice, right?

**dbosman** · 06-06-2012, 10:30 PM

Originally Posted by amirfield

Thanks for all replys, that sounds from 40-80 will be a good choice, right?

Optics aren't expensive. Order a set of each and report back to us, please. You may find you want wider optics in the center and narrow on the sides.

Some people use a really narrow optic to concentrate light on a specific coral.

**chrisfraser05** · 06-07-2012, 01:44 AM

give me 5 mins I'll find something really interesting for you..... lets just say it'll make your decision easy!

**ILuvMyGoldBarb** · 06-07-2012, 01:50 AM

It's rather easy. If you think of a line that runs perpendicular to the diode as being straight down. A 60 degree spread spreads out 30 degrees either side of that line, while 120 spreads out 60 degrees either side of that line. The lower the angle of the optic, the more focused the light will be.