An Updated LED Guide v1.1

[jedimasterben]

An Updated LED Guide
Hello all. The old 'Ultimate LED Guide' posted by Clive Bentley (evilc66)has not been updated since July of 2010 – to say LEDs have changed since then is doing them a disservice. We've come even farther as far as efficiency and output go, from 37% efficiency from the Cree XR-E at 25C to 53% efficiency from the Luxeon T at 85C. I’m going to try to cover the basics, but there is a LOT of information to cover. Bear with me, but, you know, not with an actual bear.

LED types for DIY
There are many, many LED manufacturers out there - some of the more notable are Bridgelux, Cree, Epistar, Nichia, Philips, and SemiLEDs. All of them (save for Bridgelux) make a slew of different white and single color LEDs, each with varying outputs. Typically, Bridgelux, Cree, Nichia, and Philips have the highest output of those, in addition to being the most common and easily accessible LEDs to end users, along with the reliability that comes with their name. Generic Chinese LEDs (typically from places like Alibaba or eBay) are almost all using older LED tech with higher forward voltages, lower output, and poor phosphor tech that are not consistent in their color, and should be avoided - the small savings is not worth the extra hassle. This guide will be in no way complete - I simply don't have the resources to test out every LED, but I will at least give information on what is known about them and give my thoughts if I've tested them.

Photosynthetic peaks (and the colors they reflect) for the most common photosynthetic pigments


In corals,chlorophyll a consists of about 90% of total chlorophyll content, and chlorophyll c2 makes up the remaining 10%. In Tridacna clams, the ratio becomes about 60%/40% with chlorophyll a and chlorophyll c2, respectively, making c2 much more prevalent. Note that chlorophyll b is not present in scleractinians, corallimorphs, or Tridacna clams (see Photosynthetic pigments of symbiotic dinoflagellates (zooxanthellae) from corals and clams, S.W. Jeffrey and T. F. Haxo).


LED colors for DIY
In this section, I’ll go over most of the LEDs available and what their function would be in an LED array.
In the article from Advanced Aquarist’s Spectral Distributions of LEDs: AI-Sol, Radion, Orphek, EcoRay, Mvava that compares a few pre-made LED fixtures to a few metal halide bulbs, Sanjay Joshi says the following:

As seen from the data, there are significant spectral differences between the LED spectrum and those of the most popular MH lamps. The LEDs tend to have more output in the blue regions 400-500 nm range, while lacking in the warmer regions of the spectrum. This could explain why the aquariums tend to have a "flat" look when lit by LEDs. Lack of the red spectrum results in corals and fish with red color to look lack lustre. Lack of a broader spectrum and missing quantities of output at wavelengths to promote a more full spectrum is often a concern cited with LEDs, and it is obvious when comparing the spectrums to metal halides.

Cool white (5000-8000K)
Cool white has been the primary white LED in DIY and commercial arrays since LEDs were first used over aquariums. They are typically whitish in appearance compared to warmer whites due to having less phosphor coating, so the LEDs are mostly royal blue in their output and typically have a low CRI (60-75). This can lead to poor coloration in corals without fluorescent pigments, like purples, pinks, reds, and oranges, in addition to the ‘flat’ look as mentioned above, and overall should be avoided.

Neutral white (3700-4500K)
These should be your go-to white LEDs. They have more phosphor applied than cool white LEDs, so they are about evenly split between royal blue and their 500-600nm peak. They are ‘yellowish’ in comparison to cooler whites, but that only matters if you are only using white LEDs over your tank (which for a reef tank, you more than likely are not). They will typically have higher CRI ratings than cool white LEDs (though be careful, as unbinned LEDs can still have 70 CRI minimum instead of the 80-85 CRI that you want), and will elicit better color from your corals, in addition to giving the look of the light some warmth, whereas cool white arrays will typically look harsh or ‘cold’.

Warm white (2200-3700K)
These LEDs can be used in conjunction with cool or neutral white to provide a wider spectral coverage and enhance warmer non-fluorescent coral colors (such as reds and oranges) without the need of adding amber, red, or deep red LEDs. They are also much easier to blend than the dedicated LEDs, eliminating some color banding (aka disco). The caveat with these is that mixed alone with royal blue throws a strong purple hue, and it takes significant power in royal blue to help bring the overall color temperature up.

Ultraviolet (sub-400nm)
Ultraviolet light can be damaging to human eyes in high quantities (or a focused beam such as from an LED), and lower wavelengths can do more harm than good to your aquarium inhabitants, as well. In addition, they will have very low outputs (usually sub-400mW at full current), will fluoresce floating particulate matter in your tank (which makes for a terrible-looking tank), and there really are no fluorescent pigments that are excited by this wavelength range alone, with most extending up into the 410-450nm range and can be excited by those wavelengths with much less cost and drawbacks. Recommend to shy away from them.

Violet (400-430nm)
Violet LEDs are becoming a much more integral part of LED arrays. They incite some wicked fluorescence like no other LED can, but since the human eyesight is very poor in this range, the LEDs are quite dim, and any other LED active at the same time will eliminate the fluorescent effects. In addition, violet LEDs are PAR monsters. A caveat to this is that there are many places still selling older violet LEDs that have very little output (sub 450mW) for the same price that other shops are selling for similar cost as newer, far higher output LEDs (up to 700-1,000mW) from others, so be sure to look at the rated output before buying.

Royal blue (440-455nm)
This is the second of your two base colors. This provides your ‘actinic’ spectra, which is on and near several photosynthetic peaks for chlorophyll and its accessory pigments. True royal blue is right around 445nm and LEDs can be 440-455nm but the lower the wavelength, the better it is for photosynthesis, as you’re getting closer to chlorophyll a's 428nm peak. Using higher-wavelength chips is not necessarily worse (and still has a track record of growing corals faster than anything before), as peridinin (which has a broad absorption spectrum, peaking at ~475nm) forms a bond with chlorophyll a (called PCP) and can transfer up to 95% of its absorbed energy directly to it, increasing chlorophyll a’s overall absorption spectrum significantly. Typically use one to four royal blue per white LED (1:1 with cool white, 2:1 with neutral white, and 4:1 with warm white to bring color temperature up to ~12,000K).

Blue (465-480nm)
This is a supplemental blue that is mostly overlooked in DIY arrays. The small difference in wavelength versus royal blue makes a much bigger difference than it would seem. The addition of blue (aka cool/standard blue) does three things. First, it makes more colors fluoresce than royal blue alone due to more fluorescent excitation spectra coverage. Second, it makes the fixture appear ‘brighter’ because it’s closer to a wavelength our eyes can see better than lower royal blue, helping to eliminate the dim look that some LED fixtures have in comparison to metal halide and fluorescent lighting. Third, it can eliminate the purple cast given by some NW/RB combinations (usually with lower-kelvin whites or shorter wavelength royals).

Too much of a good thing can be a bad thing, though - the color of cool blue is about on par with Windex – too many of them can make your tank look like such. I would use no more than one cool blue per four royal blue chips (to put it into numbers, use 70-80lm of blue for every 6,000-7,000mW of royal blue). The best effect from these LEDs is produced from those with a peak wavelength around 465-470nm, with higher being much more green-tinted.

Cyan (490-510nm)
This is another supplemental color. Many confuse this with green because of the green cast that typical cyan LEDs have, but they are quite different. Cyan can be used to brighten an LED array (since our eyes can see this spectrum better than violet, royal blue, and blue), eliminate the purple hue that some arrays have, and can excite some non-fluorescent red colors. When looking to add these LEDs, the closer the peak wavelength to 495nm, the better.

 

Green (520-540nm)

These LEDs will help to brighten up the light in your array, but since they have a short spectral half-width, they stick out like a sore thumb like dedicated red LEDs. Lime is a much better addition.

Lime (520-620nm)
Lime is a new LED color from Philips. Imagine it as being a white LED without the blue peak. Peak luminous output is from 566-569nm, and the spectral half-width (how much spectrum it covers at 50% luminous output) is ~520-620nm, so it covers a very broad spectrum, so it should blend well with royal blue to help prevent spotlighting. This LED is VERY bright to the eye and is an awesome addition to any LED array, and can adjust CCT easily with it. In my testing, I prefer a 50/50 usage of lime and neutral white per lumen.

Amber (585-595nm)
Amber is a part of the spectrum typically covered in high enough quantity by warmer white LEDs with higher CRI, but they can be added to help tweak certain colors if you’re anal. Amber LEDs typically have lower output and lower thermal tolerance, so take caution when adding them to higher density arrays.

PC-amber (550-630nm)
Not to be confused with amber, PC-amber (the PC stands for phosphor converted, so, like white LEDs, this one starts off life as royal blue) has a very broad spectral range, similar to lime, with the actual peak around 590nm. Also similar to lime, this LED can be used to adjust CCT without changing any other LED setting, though more shifted towards the 'warmer' spectra.

Red-orange (610-620nm)
This is another range typically included in higher CRI white LEDs. These LEDs do, however, very closely match the europium spike present in most fluorescent bulbs (notably the ATI Coral and Purple Plus, KZ Fiji Purple, Giesemann Aquablue Plus, Lagoon blue), and should, in theory, bring about the same benefits.

Red (620-645nm)
Similar in look to red-orange with a slightly higher peak wavelength, and wider spectral coverage in the case of Philips diodes.

Deep Red (650-670nm)
Yet another supplemental color, this one actually covers photosynthetic spectra of chlorophyll a in addition to improving color rendition in some situations. Deep red spectra is almost completely absent from most cool white LEDs, especially those in a higher kelvin rating, but it is also absent from most fluorescent and metal halide bulbs (in any significant quantity, anyway). Can be added to increase rendition of some non-fluorescent colors, but red or red-orange is a better choice IMHO.

Hyper Red (730nm)
These are very rarely used over coral tanks. I’ve seen data where they can be useful for specific terrestrial plants for beginning and end of photoperiods, but I haven’t really seen any that applies to corals.



Common LED brands and models
Keep in mind that the LEDs below, while very similar, will only be comparable and not exact due to binning (which selects the ‘quality’ of the LED, which is the output in luminous or radiant flux, the forward voltage at test current, and the CCT or wavelength).


Bridgelux
Bridgelux has been making high-powered white and low-power royal blue/green for remote phosphor for several years now, though being a newcomer to the industry, their LEDs are class-leading as far as color and efficiency. Their LEDs are basically all high-powered multichip white. Bridgelux, unlike Cree and Philips, separates all of their bins into product skus, so to get a 4000K 80CRI 950lm ES Rectangle Array with 3 SDCM color (which is how tight the color is between batches), you’d need SKU BXRA-40E0950-B-03. This actually makes it very easy to get the exact LED you want once you check the datasheet and figure out what you’re looking for.

BXRA3 ES
These are probably the most commonly used Bridgelux chips in DIY. The BXRA3 series has been updated and the newer diodes have better flux and efficiency and are still compatible with the same reflectors as the older style. These should be best used with a Molex adapter for ease of reflector addition and wiring.

Bridgelux ES Rectangle Array datasheet

Vero series
The Vero series is Bridgelux’s newest series. They come in four different die sizes, each with varying voltages and maximum currents, and range from a lotta flux in the case of the Vero 10 (topping out over 2,200 lumens) to immense flux in the case of the Vero 29 (which tops out at over 20,000 lumens). Reflector choice for the Vero series is still limited, however the reflectors for the BXRA series can be used on all but the Vero 29.

Bridgelux Vero 10 datasheet
Bridgelux Vero 13 datasheet
Bridgelux Vero 18 datasheet
Bridgelux Vero 29 datasheet

V series
The V series is a new addition alongside the Vero series. They are lower in overall flux, and also much smaller - the V6 and V8 measuring only 12.5mmx12.5mm, the V10 measuring 15.8mmx15.8mm. These would make great choices for reflector-less arrays over smaller tanks.

Bridgelux V6 datasheet
Bridgelux V8 datasheet
Bridgelux V10 datasheet

Bridgelux white (all are the same between series)





CREE
There have been several iterations of Cree LEDs used in aquaria. XR-E being one of the first, then moving to the XP-E, then XP-G, XM-L, and now XT-E, XP-G2, XM-L2, XP-E2, and more that are based on Cree’s patented silicon carbide wafer.


XM-L/XM-L2
The XM-L is a bit different than most other Cree chips – they are binned at 700mA (~2 watts) and are capable of running up to 3A (~10 watts). This makes the XM series Cree’s highest non-multichip single LED king. When run at lower currents, they are 15-20% more efficient than the XT-E and XP-G2, but at over twice the cost. Unfortunately, the XM-L and XM-L2 are difficult to find in quality color bins, in addition to having off-axis color issues, so unless you’re running optics and absolutely need high-output LEDs, I would avoid these and would use other diodes.

XM-L datasheet
XM-L2 datasheet

XM-L white


XM-L2 white



XP-E/XP-E2
The main use for these chips would be supplemental colors, such as blue, red-orange, and red. There are white and royal blue in both lines, but they have higher forward voltages and lower efficiency than the XT-E and XP-G2 lines, so those should be used instead. With the XP-E2 comes a spec boost, lowering the thermal resistance and increasing maximum amperage for all colors to 1A. The XP-E2 also now includes Cree's own PC amber, which should deliver a few more lumens than the Rebel PC amber and offers a slightly different spectral signature.

XP-E datasheet
XP-E2 datasheet

XP-E white


XP-E color


XP-E2 white


XP-E2 color



XP-G/XP-G2
The only chips in these lines are white. The XP-G came before the XT-E so it is a little behind it, but the XP-G2 puts it slightly ahead of the XT-E, also decreasing thermal resistance and introducing hot binning.

XP-G datasheet
XP-G2 datasheet

XP-G white


XP-G2 white



XP-L
The XP-L is what I am assuming is the successor of the XM series - boasting increased output in the smaller 3535 package that most all of the Cree LEDs now use. With lower thermal resistance, as well, this means that if you desire you can replace any XP/XT LED on an array with the higher flux XP-L, though these are still expensive diodes for around 9% more output than the XP-G2 at currents 1.5A or less - the XP and XT series are not rated beyond that, though the XP-L, like the XM-L before it, is tested to 3A.

XP-L datasheet


XQ-E
The XQ-E is one of the newest lines from Cree, packing most of the efficiency of the XP-E2 diodes into a tiny 1.6x1.6mm package. The colors include white, blue, green, PC amber, red-orange, and red (strange that they left out royal blue, but the XT-E, Rebel ES, or Luxeon T would be a much better choice unless you need that small package).

XQ-E datasheet

 

XR-E
These are the oldest that I could find from Cree that were used for reef aquariums. They were available in white, royal blue, blue, and green. They very inefficient compared to modern LEDs, so these should be avoided.

XR-E datasheet

XR-E white


XR-E color



XT-E
The XT line is Cree's 'standard' line for white and royal blue, being the most readily available and typically less expensive of their modern diodes. They were the first from Cree with hot binning, but as far as color goes they are expensive to acquire in the US in good bins, the 'reef LED' shops all sell unbinned diodes.

XT-E datasheet

XT-E white


XT-E royal blue





PHILIPS
LEDs from Philips are gaining ground on Cree in the hobby, boasting efficiency equaling or exceeding their competitors along with better bin availability and better color.


Luxeon K
The Luxeon K is a multichip package that uses the full Luxeon T package on a small, packed PCB. They are available with emitter counts from 3-24x for white and 8x or 16x for royal blue.

Luxeon K datasheet

(See the Luxeon T section for spectral data)

Luxeon M
The Luxeon M is a quad-die multichip LED that uses four of the Luxeon T diodes in series, so the forward voltage range is 11-11.5v typical, but the output is four times higher. These LEDs pack some serious punch and can significantly reduce complexity and time spent building an array.

Luxeon M datasheet

Luxeon M 80CRI white


Luxeon M royal blue



Luxeon T
These LEDs are the eventual successor to the Rebel series, as Philips is wanting to move away from their proprietary package. These are their highest efficiency single LEDs and are in a 3.7mmx3.7mm package, slightly larger than the XT-E at 3.45mmx3.45mm. Unfortunately I have not seen these LEDs available mounted as of yet.

Luxeon T datasheet

Luxeon T white


Luxeon T royal blue



Luxeon UV
The Luxeon UV is Philips’ latest venture, this time into UV and near-UV diodes. They bring along some of the highest efficiency at this time, as well as being micro-sized - just 1.2mmx1.7mm, enabling four diodes to be put into the same area as a single XT-E or Luxeon T. Their forward voltage is also lower than has been seen before with violet diodes, coming to just around 3.0-3.1v The caveat is their price - which hovers between $10 and $15 per diode depending on wavelength and flux bin. These are not available mounted, but they are readily available from several vendors.

Luxeon UV datasheet


Luxeon Z/Z ES
The Luxeon Z continue Philips’ foray into micro-sized packages, keeping the 1.2mmx1.7mm size of the Luxeon UV. The Luxeon Z ES is a higher-flux option, and while still micro-sized, they are slightly larger than the standard Z, at 1.64mmx2.04mm. The Z ES has the same solder pad layout as the Luxeon T.

Luxeon Z & Z ES white datasheet
Luxeon Z color datasheet

Luxeon Z white
(see the Rebel ES or Luxeon T or Luxeon M)

Luxeon Z color


Luxeon Z lime



Rebel/Rebel ES
These are competitors to the XP-E/XP-G/XT-E series, and have similar efficiency. The royal blue Rebel ES run at 1.5A is the highest output royal blue single LED on the market, though at 1A the Luxeon T takes the crown.

Rebel ES white datasheet
Rebel/Rebel ES color datasheet

Rebel ES 4K 80CRI


Rebel ES 5K 80CRI


Rebel/ Rebel ES color


Rebel/Rebel ES lime/PC-amber





Stay tuned for more on LEDs, drivers, power supplies, optics.



Also, please try and keep this on topic - discussing the contents and any suggestions, this thread isn't to be made into an LED vs xxx debate, or a 'what should I use for my tank, help me' thread.

 

v1.0 - initial release

v1.1 - updated XP-E2, added XP-L and XQ-E

[metrokat]

Needs a sticky IMO.

[Horerczy]

Looking good Ben. Gonna add anything about premade fixtures In?

[jedimasterben]

Probably not. This one will keep in the DIY scope.

[Nano sapiens]

Yes, sticky in the lighting forum for sure. Great write-up and very helpful info.

[zooman72]

I agree - this should be stickied as a lot of work went into it - someone get CM's attention, stat!

 

 

Nice work here Ben - only thing I might mention (or add) is that the use of cool whites may work for some if they are balanced with warm whites, especially as it can result in a "brighter" light to the eye, and can be a potential option for some if they don't want all neutrals or are trying to update an older fixture or modify a newer one.

[miked0305]

You are definitely a Jedi master I have been looking for something like this for two weeks. This definitely helps alot.

[HM3105]

Thank you!

[LynkUK]

There is no other word for this but...AWESOME!!

 

Many thanks

[Nano sapiens]

Nice work here Ben - only thing I might mention (or add) is that the use of cool whites may work for some if they are balanced with warm whites, especially as it can result in a "brighter" light to the eye, and can be a potential option for some if they don't want all neutrals or are trying to update an older fixture or modify a newer one.

 

I'll have to second that. I found that a small amount of cool white (and blue) had a positive effect by taking the edge off of the look of the neutral white's a bit.

[frankdontsurf]

I keep reading this over and over and im understanding more every time. Thanks for the work Ben.

 

Question: for a diy array do you end up canceling out certain wave lengths by mixing colors?

 

For example, I have GU10s 3x3w, 5 are blue, 2 are cool white and 2 are warm white. Does this combination affect the peak colors in the WW or CW spectrums? This question is specific to what I have but I mean it in general for any colors. I know Ben likes to stock the Violets heavy... Or is it "more is better"?

[jedimasterben]

Light from additional LEDs is additive, not subtractive like it would be if it were a single bulb. For example, you can't take an LED with 100 lumens of output that emits 80 of blue and 20 of everything else, and then up the everything else to 40 lumens without lowering how much blue is emitted.

 

 

That being said, light that is heavy in any part of the spectrum relative to the others will certainly drown out colors. Crank up your white LEDs while leaving blue spectrum where it is and fluorescence that you can see is reduced.

[f4tal reefer]

Perfect timing. Just began looking into DIY for my 14g biocube I plan to derim. And for the planning of my 40g breeder build. Thank you.

[1.0reef]

Jedi Master STICKAHHH!

[SMDavis]

TTP for the purpose of great information.....

[jedimasterben]

Made a few slight changes here and there, mostly just edited in info about lime.

[Paleoreef103]

Made a few slight changes here and there, mostly just edited in info about lime.

Are you going to update the standard reds now that you are using those as well? What do you think of the 630 nm reds?

[jedimasterben]

Are you going to update the standard reds now that you are using those as well? What do you think of the 630 nm reds?

I really only put those into my build because I couldn't think of anything else that I wanted to fill in those spots on the tristars. I doubt that they would have an appreciable effect while the 4000K 90 CRI Vero 10 are in use - that being said, if I were to completely shut off the Vero array and use lime to make the 'white' source, then I could see them being helpful, as they do hit the spectra that T5 do, though it would be best to use PC amber to fill in a bit, as well, in that warmer spectrum.

[pgrVII]

Ben,just got done reading this thread and its very informative. Good work sir.

[jedimasterben]

Thanks!

[nova423]

Great write up, Yoda himself would be proud

[jedimasterben]

[welight]

Hope you dont mind if I drop in some pertinent Cree updates you might like to add

• Cree XPE-2 PC Amber, fluxes out same as Rebel however max drive current 1 amp vs Rebel at 700ma so can provide 216 lumens at 1Amp, Tj is 150Deg vs 130 on Rebel, thermal resistance 9d c/w vs rebel 10. Also available in Cree XQE 1.6mm x 1.6mm package
• Cree XQE 1.6mm x 1.6mm with a primary lens, typically 10-20% brighter than Luxeon Z, but I know it does not come in lime, Deep Red or UV, however keep in mind Z come is 4 footprints and lens heights so can be a bit of trick re assmbly
• Cree XPL, just released, true 200 LPW single die led, XML in XP footprint, 3A drive max come sin 90CRI versons in warm and mn 80 in Neutral

[jedimasterben]

 

Hope you dont mind if I drop in some pertinent Cree updates you might like to add

• Cree XPE-2 PC Amber, fluxes out same as Rebel however max drive current 1 amp vs Rebel at 700ma so can provide 216 lumens at 1Amp, Tj is 150Deg vs 130 on Rebel, thermal resistance 9d c/w vs rebel 10. Also available in Cree XQE 1.6mm x 1.6mm package
• Cree XQE 1.6mm x 1.6mm with a primary lens, typically 10-20% brighter than Luxeon Z, but I know it does not come in lime, Deep Red or UV, however keep in mind Z come is 4 footprints and lens heights so can be a bit of trick re assmbly
• Cree XPL, just released, true 200 LPW single die led, XML in XP footprint, 3A drive max come sin 90CRI versons in warm and mn 80 in Neutral

Thank you - I've added their data into the guide. I see that you carry the XP-L and the XP-E2 PC amber, good to see that they're already available.

[welight]

Cree Update: Cree have released XPE in Photo Red 660nm