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Thread: Need some help choosing LED colors

  1. #1

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    Need some help choosing LED colors

    Ok just so everyone knows I have built a few LED fixtures for over my display tank so I have a solid understanding of the way to build fixtures and how they work. BUT this build is for my scrubber so I am going to need some help My screen is about 10" long and about 8" tall with tons of flow. As of now it is lit with four 23 watt CFL lamps. I feed about 3 cubes a day but that can vary some due to my work schedual.

    My plan was to use six 3watt CREE LED's on each side of the screen. (enough?)

    I was going to use 3 red and 3 cool white on each side.

    My thinking is that the cool white will have enough blue light in them while still providing other parts of the spectrum.

    I have read something about blue light "overpowering" other parts of the spectrum causing people to run them at a lower power? What is this all about?

  2. #2

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    As far as i know. Cree dont make 660 nm leds. So you'd needs osram or some others.

    Ive got 5 warm white (3000k) 5 cool white (6500) and two blue (which im looking to replace with 2 660nm reds)

  3. #3

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    I should say. Im new to scrubbers. But it seems to be working really well. its starved the cyano within 3 weeks. Just got the GHA in the display to deal with now.

  4. #4

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    I had the same problem and was advised to have 660nm reds and royal blues in the ratio 6:1 or even 8:1

    Dennis

  5. #5

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    I'd stick with blues (455 and maybe 420 if you can find them) and reds (660 and maybe a 630) where the known peaks of photosynthesis are. I would note that the "best" combination of spectrum to use is still an open question. Until more people try out more combinations, we won't really know. Consider anything you do an experiment, and don't be surprised if someone comes up with a better design or if yours ends up not growing that great. Fortunately LEDs are cheap and pretty easy to swap out if you end up needing to change.

    I can tell you that my current set up with 10 660nm and 4 630nm LEDs per side grows a really good volume of algae, but it doesn't seem to be enough to completely outcompete my display lights, which are a combo of 450nm, 460nm and cool white. I've got some spots where algae persistently grows in the display. I've got 10 450nm LEDs on order to add to the scrubber to see if that helps. Based on my experience, and against advice I gave prior on this site, I definitely would not go all red at this point.

  6. #6

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    my display has 24 cree led's 12 royal blue and 12 cool white over a tiny 45 gallon cube running at full power and I have almost no algae in my display tank using the four 23 watt cfl's on my scrubber, are you saying that this could change if I upgrade to led's??

  7. #7

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    Could be... I get much more growth volume on my scrubber now than I did with T5HOs, but I'm struggling with algae in the display that I didn't have before. The proper mix of wavelengths hasn't been nailed down. If things are going well with CFL and you don't want to risk it, then wait. My guess is that within 6 months there will be a consensus on which wavelengths provide comparable growth. Your display LEDs are comparable to mine (126 CREE XR-Es on a 125 gallon tank).

    Quote Originally Posted by greenmachine View Post
    my display has 24 cree led's 12 royal blue and 12 cool white over a tiny 45 gallon cube running at full power and I have almost no algae in my display tank using the four 23 watt cfl's on my scrubber, are you saying that this could change if I upgrade to led's??

  8. #8

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    seems like all we need to do is get some spectrum graphs of common cfl's used on scrubbers then mimic the spectral output using combination of the right led's

  9. #9

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    Not really. The promise of LEDs is to use the spectrum much more efficiently. If you use the exact same spectrum as CFLs, you won't get any energy savings with LEDs.

  10. #10

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    Are you guys using optics on your led scrubbers? How far apart are they? Cfl/t5 put off a lot higher par numbers a new cfl at 4" has 600+ par and this is with cheap walmart lamps. T5 at 2" is more like 800+ been a wwhile since I've done par meter tests but leds are much less unless u put them close together and use optics even then my leds over my yank only run like 400 at water surface but at corals its 300-350 sand bed is 250 not a lot of drop off through water unlke other lights. With leds anything over 400 and corals bleach MH/T5 the numbers are much higher. There's been a lot of testing In our local reef club who has an apogee par meter the $350 one. I'm guessing that the reason for your display algae is that you have more par in your tank then with your scrubber. Adding more leds should fix this which is why I'm wondering how much spacing and if your using optics. I'm looking to build a led scrubber also but my cfl one works so good hard to switch especially since leds are all just testing and I have yet to see anyone mention any par numbers with any scrubber. On a side note a cfl bulb after 3 months drops down to 50-75 par from 600+

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