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LED Colors, And What They Are Used For


evilc66

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I've seen magenta LEDs in some products recently. What's the general consensus on them? Would they make a good fuge light addition?

 

 

'Magenta' LEDs are blue LEDs with red phosphor or are dual-chip royal blue and red.

 

 

So then they would be good for turf scrubbers and fuges?

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So then they would be good for turf scrubbers and fuges?

They should be if you can find quality ones which doesn't seem that likely. I'd rather have discrete chips that are of known quality than a single chip of unknown quality.

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jedimasterben

So then they would be good for turf scrubbers and fuges?

Don't bother IMHO. Algae scrubbers you want 660nm deep red and either royal blue or violet in a 4-8:1 ratio, and refugiums around the same unless you want it to be on display.

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I've never seen magenta/pink LEDs in more than 1/4W packages (5050 and the like), and even those are hard to source. It's not worth the effort. Even in the fixtures that they are used, the general consensus (that I've seen anyway) has been that they kinda suck.

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  • 2 months later...

so if I were trying to make just strait up grow lights, I don't care at all how the corals look under them, I just want optimal spectrums for growth. I'm thinking 3x 10LED pucks over a 20 long. My idea was the following, but should I be doing a different ratio, or different colours?

 

2x 420nm violet

1x 660nm deep red

1x 500nm cyan

3x 445nm royal blue

3x 470nm blue

 

in the outside pucks, and the centre puck has a 620nm red instead of the deep red, and a 405nm violet instead of the cyan

 

any ideas? suggestions? i feel like its gonna look UGLY hahaha obviously, on a dimmer, so that its not WAY too much light

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jedimasterben

If you're just wanting growth, then use some royal blue and warm white and call it a day. Do not cluster the LEDs, space them out in rows. Yes, it'll look like garbage, but distributed light will net better growth.

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If you're just wanting growth, then use some royal blue and warm white and call it a day. Do not cluster the LEDs, space them out in rows. Yes, it'll look like garbage, but distributed light will net better growth.

if we use blue, and TV, and red, and whatnot to supplement for growth in our display tanks, would it not be smart to also use them for a grow light? Its gonna be over a very low nutrient tank, with no fish, so i'm not too concerned with algae growth. I totally agree with spreading them out though, just had an option of having custom cree multi chips made, for cheaper than getting the individual LEDs on stars.

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jedimasterben

if we use blue, and TV, and red, and whatnot to supplement for growth in our display tanks, would it not be smart to also use them for a grow light? Its gonna be over a very low nutrient tank, with no fish, so i'm not too concerned with algae growth. I totally agree with spreading them out though, just had an option of having custom cree multi chips made, for cheaper than getting the individual LEDs on stars.

You just need intensity for growth.

 

And FYI, if you can get 'multichips' from Cree made for cheaper than individual stars, more than likely they aren't Cree.

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You just need intensity for growth.

 

And FYI, if you can get 'multichips' from Cree made for cheaper than individual stars, more than likely they aren't Cree.

nah they're just more than likely lower bins. the manufacture I deal with is strait up with me about when I end up with epiLEDs vs Cree, normally just because Cree doesn't make some of the spectrums I ask for :P and the cost per chip would be less when theres only one PCB instead of 10 individual stars for each chip.

 

regardless,

 

if intensity is all thats needed for growth, then why do we include all the other spectrums (other than for visual appeal) in our display lights? corals use more than just 450nm and the minimal amount of red that comes from warm white?

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jedimasterben

if intensity is all thats needed for growth, then why do we include all the other spectrums (other than for visual appeal) in our display lights? corals use more than just 450nm and the minimal amount of red that comes from warm white?

Visual appeal. Same kinda thing for terrestrial plants. The most used growth peaks are 660nm and 450nm, and are what grow lights use almost exclusively for the highest growth potential.

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Visual appeal. Same kinda thing for terrestrial plants. The most used growth peaks are 660nm and 450nm, and are what grow lights use almost exclusively for the highest growth potential.

so then wouldn't it make sense to use 450 and 660, maybe some 470 as well in the frag tank? why bother with white?

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jedimasterben

so then wouldn't it make sense to use 450 and 660, maybe some 470 as well in the frag tank? why bother with white?

Because while a lot of research has gone into what wavelengths corals use, it varies not only between species, but specimens from slightly different locations and depths. Plus, with the white LED, you will have at least enough color rendition to be able to tell how the coral is doing at a glance, if there is any tissue recession, etc.

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so you figure the best option is just a strait up 2:1 ratio of royal blue to neutral white, and lots of it? no point even bothering with violet and blue?

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  • 4 weeks later...
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This is not what this thread is for. Please ask that somewhere else.

 

EDIT: I wanted to clarify why I said this seeing as there is other discussion on this thread. The question came off more like a "will this work for my tank" kind of question. That's not what this thread is about. The discussions prior to this have been about how to set up an array to get the most out of it as far as color is concerned.

 

Questions like the following are allowed:

  • Why should I add XXXX color LED?
  • My XXXX coral looks terrible. What can I do to make it look better?
  • How will XXXX color affect growth/color?
  • etc...
  • Like 1
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Yay! Sticky!

I'm sort of a newcomer to Reef tanks and this post is a little late but i really appreciate the time and effort you put into developing this thread and then getting it stickied. It has helped me understand LEDs and their coloring which allows me to better search for an appropriate light and then adjust the colors accordingly.

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You (and everyone else) are very welcome. As anyone who has been around on this site long enough will tell you, I'm all about helping spread the LED love :)

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  • 1 month later...
twilightmmj

So, I've been seeing a number of requests over time about what the various colors of LEDs do for the tank, and the quality of the light, so I figured I would write up a quick post to go over the high level overview of what each color of LED offers to you. I'm not going to get into the biological nitty gritty here (Jedi is better at that than I am), only coral color rendering ability, and light quality.

 

White

 

Virtually every LED setup uses white LEDs as part of the base for the color of the light. The main reason for this is that is covers virtually all of the visible spectrum, and fills in some of the valleys that direct color LEDs miss. Different color temperatures (CCT) offer different effects, with some features being better or worse depending on the CCT.

 

Cool White (6000K and above)

While being used in the industry for the longest time, they aren't necessarily the best option due to the generally poor color rendering offered. They traditionally lack a lot of red content in their spectral output, and as a result, make reds, oranges, and pinks look dull. The higher the CCT, the worse the effect, and the more cold and stark the light will end up looking.

They do have an advantage in efficiency and output over warmer whites, and can be useful in full spectrum setups that have a lot of diverse control over the spectral output. As a general rule though, they aren't the preferred option, even though most mass produced fixtures use them.

Neutral White (4000K-5500K)

These are generally accepted as the go to base white color. The increase in red output, as well as the reduction in blue really helps with overall color rending, and the CRI (color rendering index) is usually a lot higher. Even cheaper neutral whites will have a CRI of 70 or greater, versus around 60 CRI for a typical 6500K cool white.

The relative output compared to cool white LEDs in the same series is lower, but not by as much as it used to be. It's not really that great of an issue though, as the blue LEDs will generally make up for any loss in performance, and the advantage of the higher CRI completely outweighs any loss in output and efficiency.

Warm White (2700K-3500K)

While not generally used by themselves as the base white, they are great when used in tandem with higher CCT whites. Warm whites will have very little blue output, lots of red, and very high CRI, with some of them getting up to 98 CRI. These are a great way to add warmth to the light, and improve color rendering in reds, oranges, and pinks without resorting to direct color red LEDs, as they tend to blend far better with the rest of the array.

Direct Color LEDs

 

Direct color LEDs make up the bulk of the color options available right now for LED setups. The material and doping process for the LED die creates the emission wavelength of the LED without any modifiers, like phosphors that are used in white LEDs. Because there is no down conversion of the energy emitted by the LED die, the efficiency on these LEDs is generally very high. They are very peaky though, meaning they emit light in a very narrow range, and the various color don't overlap a lot. This is the reason that white LEDs are used in conjunction with direct color LEDs, so the valleys between the different wavelengths is filled up, even if it's only a little, depending on the wavelength. We will start low and work up in wavelength.

UV-A (315-400nm)

Ultraviolet light is in the 100nm-400nm range, with UV-A being the 315nm-400nm end of the spectrum. UV-B and UV-C are not even considered here, as they are damaging to tissues. UV-A doesn't get used very often either, but will be found in every fluorescent and gas arc discharge (metal halide, HID) lamp due to the mercury used. Some, including myself have speculated that UV-A can actually be beneficial for coral health and color, but hasn't been proven effectively (at least from what I have seen so far). The big detractor from UV-A LEDs, especially in the 365nm range (mercury spike) has been cost. They are outrageously expensive, and with little known benefit, are generally avoided. UV-A LEDs hovering around the 400nm range aren't really of any use, and the photosynthetic action curve falls off sharply around this point.

As for coloration in the tank, there is very little discernible difference when these are used, as the human eye isn't very sensitive to these wavelengths. When used alone though, they can bring out fluorescent colors that aren't normally seen when using light in the visible spectrum. Due to the potential health risks though, especially regarding the eyes, they aren't recommended for use.

Violet (400-440nm)

Violet LEDs are for growth, not color. Like UV LEDs, the eyes aren't all that sensitive to this light, so the effects when used in conjunction with the primary white and blue LEDs are minimal at best. What they are good at is producing PAR, and lots of it. These are a great way to add growth potential without messing with the color temperature of the light. Caution should be taken with LEDs in this wavelength range, as you can't tell how intense they are, but the corals certainly will. Without proper care, corals can be easily bleached.

Royal Blue (440nm-465nm)

Royal blue LEDs are the muscle used to bring up the color temperature to more reef friendly levels, as well as producing a lot of PAR. They are also one of the best producers of fluorescent colors in corals. Royal blue, compared to blue (or cool blue as some call it) is a deeper color that doesn't illicit the "Windex" look. LEDs in the 440nm range tend to look a little more purple compared to common 450nm-455nm LEDs. When combined with neutral or warm white, the overall light can look a little purple, with the effect exaggerated the lower the CCT of the whites get, and the lower the wavelength of the royal blue LED.

Blue (465nm-485nm)

Blue was initially considered a supplemental color, meaning that it made an effect to the light and coral color, but wasn't really necessary. That's changed though, and it really is a beneficial color that should be used in all arrays, although sparingly.

Blue LEDs do a great job of fluorescing reds and oranges that royal blues just can't touch. They also help to take some of the purple tint out of the light that you can get from a neutral/warm white and royal blue mixture, as well as making the light a little crisper. Too much though, and the tank can look like Windex, so they either need to be used with restraint, or put on a separate channel to be controlled independently.

Cyan/Turquoise (485nm-500nm)

Cyan, or turquoise, is on the falling edge of the large blue photosynthetic peak, so it's not great for growth purposes, but it does have some useful effects on the color of the light and corals. Much like blue, cyan brings out fluorescing colors that other wavelengths don't. they are also good at making the light more crisp, and reducing the purple tint that you can get. It's another color that has to be used sparingly, but it's not as damaging to the color of the light as blue is.

Green (520nm-550nm)

Green does very little other than making the light brighter to the eye, and helping to reduce the purple tint. It really doesn't make anything fluoresce in a way that other colors would, and provides virtually no growth benefit.

Amber (585nm-595nm)

Amber is not used very often, as it doesn't produce much effect. It can help increase color rendering with cool white LEDs, but warmer whites typically have higher amber content anyway, so they don't provide much benefit.

Red-Orange (610nm-620nm)

Red-orange falls into the same boat as amber.

Red (620nm-645)

Red can help with color rendering more than amber and red-orange, as this is the area that most cooler white LEDs are lacking. It's also more in the red photosynthetic peak, so it has some growth benefits. Because our lighting setups are generally more blue heavy though, red can be very distracting when not used properly. Generally, warm white LEDs can be used to better effect to get the same color rendering advantage.

Deep Red (650nm-670nm)

Deep red doesn't have as great of an effect on color rendering as red does, but it can help with very specific color requirements. It was believed to have better growth properties than red, but that idea is starting to fall out of favor. Deep red is being used less and less.

Phosphor Converted Color LEDs

 

This is a fairly new development in LED technology. These LEDs use a royal blue LED as a base, much like white LEDs, but use selective phosphors to produce a different color. Unlike direct color LEDs though, the output is over a much larger range of wavelengths, and can have some greatly different effects compared to their direct color counterparts.

Lime (566nm-569nm)

566nm-569nm is just the peak wavelength, as these LEDs produce light in the 500nm-620nm range (measured at the 50% output point). The peak wavelength is higher than a typical green, and it actually coincides with the peak human eye sensitivity. This LED was designed with that in mind, as it was intended to help brighten the light, without adversely affecting CCT (something that just green alone can't do). This color can make the light a lot brighter as well as completely eliminate the purple tint that you can get with neutral white and royal blue combinations.

PC Amber (588nm-592nm)

Much like the lime, that's just the peak wavelength. Emitted light ranges from 540nm to 625nm (measured at the 50% output point), and is more intended to help with color rendering without negatively affecting CCT. Much like the lime, it can easily replace amber and red-orange to better effect.

So there you have it. A reasonably easy to digest guide to LED colors. I don't want this thread to get into a discussion about what LED combo to use. There are other threads that deal with that. But please do let me know if I've made any obvious errors or omissions.

 

If you guys find it useful, I'll petition a mod to make this a sticky.

Great post

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  • 4 weeks later...
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You have been very helpful :-)

Your simple language to explain it is nice. Article gives me good understanding of LED things to me.

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Great thread and great info on this site. Found it when researching my upcoming build. I know the Vero 10 is the most popular white, and I was planning to use the 4000K 90 CRI. The thing is, I was looking at the datasheet for the Luxeon K 4000K 80 CRI, and it seems to cover the cyan/turqouise frequencies better than the Vero. So would I make a big mistake if I went with the Luxeon instead of the Vero? Is the color rendition much better with the Vero since it is slightly higher CRI?

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You would be much better off with the Vero. While the LuxK may have more cyan, it's not necessarily for the better. The higher CRI will do you more good in the long run. If you need more cyan, then add a few to the array and control them independently so you can get the results you want. Increasing CRI after the fact is a lot harder than adding a little more cyan.

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