# Consensus on LED color for planted tank?



## tentacles (Nov 28, 2011)

I have cree 5500k and bridgelux 4500k over my 2 tanks, and I rather like both color temps. IMO any higher and they start to look pretty cold for a planted tank. I'd bet some of the 80 CRI 4000k ones would look pretty good too, although that might be pushing it. The high CRI versions' red spectrum extends farther towards infrared, rather than just having more of the same, and they also have more cyan/deep green spectrum.


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## samamorgan (Dec 31, 2011)

6500k, just like almost everyone uses with T5, is perfect. The little bit of blue really makes fish stand out, and the greens look a little more vibrant to me. anything under 5000k seems to look washed out.

This ought to help you out with choices. It's really all personal preference:


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## Geoscouter (Feb 22, 2011)

Hmm. When I check the LED specs on Rapidled it says the cool white are 5000-8300k and the neutral white are 3700-5000k. Not sure how that relates to 5500k or 6500k in the previous two comments. Seems like a pretty big range on these. Does the range mean that these LEDs cover that all of that range or somewhere within that range. If somewhere within that range is it controllable or just the luck of the draw as to where it outputs.

Either way it looks like cool white is more likely to cover both 5500 and 6500 than neutral white.

As far as which lens to get since these will be sitting on the glass top approximately 16" from substrate I think 80 degree will work best but not sure. Any advise?


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## sns26 (Mar 29, 2010)

(a) At just 16" from substrate you could probably go without lenses at all. My fixture is probably 28" from substrate and 60 degrees has worked well for me.

(b) I'd encourage you to spend some extra cash and install two dimmable drivers, each with different color temp leds on them. I run 27 XPs over my tank on two strings. One is 14 neutral and warm whites, the other is 9 cool whites and 4 royal blues. I often find myself tweaking the relative intensity of the two strings, sometimes just for a new look.


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## Hoppy (Dec 24, 2005)

You can't relate Fluorescent light or LED light color temperatures to sunlight color temperatures. Sunlight's spectrum is a smooth curve, with a broad peak offset from the middle. Fluorescent light's spectrum is a series of sharp, narrow peaks, superimposed on a relatively smooth curve. LED light's spectrum is a relatively smooth curve, with a additional broad somewhat narrow peak usually in the blue region. Comparing their different color temperatures is like apples to oranges.

You also can't use CRI as a criteria. CRI is actually just a comparison of the light to that from incandescent bulbs, which don't look good at all as aquarium lights. No fluorescent bulb can have a CRI of 100, but most incandescent bulbs have a CRI of 100.

LED production runs produce individual LEDs with a variety of "color temperatures". They are "binned" in numbered groups according to their color and their intensity. You can buy various bin LEDs to get close to the "color temperature" you want, but it isn't normally specified as a color temperature, but as a chromicity rating.


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## fizzout (Jun 7, 2011)

I appreciate the technical information, but it sounds like a matter of individual preference and that either cool white or neutral white LEDs are acceptable.

Does one LED perform better than the other with respect to growing plants?


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## pucksr (Jan 27, 2011)

*Has anyone actually experimented with this?*

I have a question. Has anyone experimented with this, or is everyone just coloring for look?

i.e. Since my understanding is that blue and red light fuel the photosynthetic process, would an all blue/red light setup grow the best? I imagine if it did, green LEDs or white could always be added for "appearance". It might also make more sense to lens your red and blue LEDs, but not your green/white.

Just curious, since I will be redoing my fixture soon.


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## h2oaggie (Feb 28, 2011)

I went with all cool white leds on my fixture and I am more than happy with the color. If I had to redo it I would add slightly more blue in the form of some XR-Es, but overall just cool whites looks good.

Sent from my SAMSUNG-SGH-I727 using Tapatalk


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## samamorgan (Dec 31, 2011)

pucksr said:


> I have a question. Has anyone experimented with this, or is everyone just coloring for look?
> 
> i.e. Since my understanding is that blue and red light fuel the photosynthetic process, would an all blue/red light setup grow the best? I imagine if it did, green LEDs or white could always be added for "appearance". It might also make more sense to lens your red and blue LEDs, but not your green/white.
> 
> Just curious, since I will be redoing my fixture soon.


You most likely wouldn't be able to pull this off, things would just look strange. Look at hydroponic grow lights, theyre a mixture of blue and red only and they make things look awful, but plants love them. You could probably try to balance it out with other colors like you're saying, but ill bet it would be much more hassle than it's worth.


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## pucksr (Jan 27, 2011)

I agree, but I was just curious if the actual color of white mattered much beyond personal preference? 10,000K White just looks better than 5000K white, and there are no other advantages?

I also ask because if blue and red LEDs are so much better for growth, then a bit of them in your mix is always going to be a good thing.


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## sns26 (Mar 29, 2010)

I think all of us who have DIY'd LED fixtures have had good growth. Could we get even better growth? Maybe. But I think most of us would not sacrifice aesthetics for it. I say pick the LED mix that you like the look of. The plants will grow (assuming you take care of them in other respects).


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## tentacles (Nov 28, 2011)

If you want to check out the various spectral graphs of different LEDs, http://www.1023world.net/diy/spectra/ has a fairly comprehensive database. It may take a while for the program to load, and you have to use a scroll wheel to scroll through the list. Some of the graphs are slightly off, for example the Citizen LEDs listed there don't extend QUITE as well to 700nm as the graph there shows, but it's the best of any LED I have seen. I ordered some of these 5000k 85 CRI LEDs, I want to see how they look. They have a quite flat color curve, with more cyan and deep red, proportionally, than any other LED I've found. Looking at the chart on 1023world, it would seem that many LEDs really lack the cyan/light blue spectra, and some are *really* bad in this respect.


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