LED Intensity

[Aquattro]

A question came up in a different thread, asking why almost everyone runs their LEDs at less than 100%, often much less. Why is that?

Does it not make sense, mathematically, that if I run 4 lights at 50%, I can get the same results with 2 lights at 100% ? Sure, coverage is a different, but lets say 3 lights, higher up but brighter, doesn't that do more than 4 lights at 60%??

So what do you run your LEDs at, and why?

[Nano]

I have my AI Sol, running at about 35% over my cube, I find anything higher is too bright, and ticks off the coral. From what I am seeing online and first hand, LEDs are right up there with MH in terms of brightness, but are not as prone to browning out corals.
I think that if you dont mind minor dark areas, you can definitely run them higher hang them higher and get the same results, also as we know many leds have options on optics that you can choose from, I believe AI has 70 or 90 degree, I cant remember which, but with a wider lens I see no reason that you couldnt run less lights at higher intensity. after all, to me 4 sols on a 4' tank seems like a waste, 2-3 would be more then adequate. provided they are suspended just right. It may limit what you can keep on the sand bed once you get to a certain height, as we know light gets less intense the deeper it has to penetrate, but for me, my softies on the sand bed and sps high, lps low to middle, it seems to be perfect! thats just my opinion though

[Reef Pilot]

When I first installed my Radions, I started them at 30%, and they were still brighter than my old T5's. I then raised it to 40%, but noticed that my corals were shrinking a bit, so I dialed them back to 30%. Since I don't have any SPS (only softies and LPS), I thought I would go even lower and see how they do. I am currently running them at 20%, and corals are doing better than ever now. Seems like my softies just don't like bright light.

I have a 6ft tank, 18" deep, with 3 Radions 8" above the water. I use the natural mode setting, so it gradually ramps up and peaks at mid day, and then down again to dusk. Then a low blue for moonlight thru most (totally off for about 3 hours) of the night.

[justincgdick]

From a mathematical perspective, you will have more uniform par if the lights are higher up, assuming you have lights strong enough. There will be a drastic difference between par at the surface and at the sand bed if the lights are in the rim. If you can raise the light up a few feet the difference in par will be less.

[WindowMaker]

there is also the factor that constantly running an LED at 100% will cut its lifespan almost in half.

[StirCrazy]

Originally Posted by Aquattro

Does it not make sense, mathematically, that if I run 4 lights at 50%, I can get the same results with 2 lights at 100% ? Sure, coverage is a different, but lets say 3 lights, higher up but brighter, doesn't that do more than 4 lights at 60%??

if you get the hights proper so PAR is the same yes you can do the same if not better with two as you will have better color blending and such. you will still get good life off the LEDs as they are rated to be run at there max power, and if you can keep them cool that will not be an issue anyways.

the issue you will have is less ability to customize colors as you already are at 100%, you will have more light spillage, and you will have a stupid fixture hanging 4 feet above the tank.

Steve

[Aquattro]

Originally Posted by WindowMaker

there is also the factor that constantly running an LED at 100% will cut its lifespan almost in half.

That makes sense, but when the industry is stating X number of years worth of life, at what intensity are they rating them?

[Aquattro]

Originally Posted by StirCrazy

the issue you will have is less ability to customize colors as you already are at 100%, you will have more light spillage, and you will have a stupid fixture hanging 4 feet above the tank.

Steve

That makes sense for color blending. I'm thinking run white at 100% then tweak the blue. Not actually having one makes for lots of guessing and assumptions
not thinking 4' off the tank, but maybe 14" or so.

[troni]

Originally Posted by WindowMaker

there is also the factor that constantly running an LED at 100% will cut its lifespan almost in half.

its lifespan is determined by running at 100%.
what i think you mean running them at a lower percent will increase life.



I'm curious as how long till the spectrum starts to change, if at all.

[Nano]

Originally Posted by troni

I'm curious as how long till the spectrum starts to change, if at all.

I "Heard" once 5% per year at 100% but I am sure that not accurate, and could be more. also depending on the types of features you use (I.E) thunderstorms etc, it could cause varied results IMO.