Open letter to the LED industry

[TropTrea]

Interesting stuff Dennis. This most recent article is the first time I've seen anything on red light and photinhibition.

It still doesn't tell us anything about red light in aquarium lighting beyond the very general "too much is not good". To make this meaningful we would first have to know what the light levels of various red frequencies is in different types of aquarium lighting. Next we would have to construct some experiments to vary the red light on said lighting to find a point at which red light appears to affect the health of corals. Lastly we would have to repeat those experiments to validate them...


Has anyone ever put that much light of any type over an aquarium without bleaching? There are so many things affecting a corals health and this is ability to respond to stressors.

You know, looking at this last statement, it is entirely possible that, in our aquariums, corals are even more sensitive to red light.

The original long article or paper did exactly what your talking about. I believe it was over 50 pages long with about 40% of it being completely Greek to me. But the end summary of the results was very plainly stated. Basicly it stated that:

In Nature Shallow water corals receive almost 10 times the light they realy need if you eventuate on a PAR bases. Some corals detect when they are getting too much light and shut down when they are receiving too much light. The mechanism they use to indicate when they are receiving excessive light is there detection of light at 630 or more nm and especially at 680 nm. Excessive light at any wave length can be detrimental to the corals if it is not in proper balance that allows the protective properties to be triggered. Different Corals have different limitations on how much light is excessive and shuts them down while others corals may may not have reached there threshold of adequate usable light at this same quantity of light. Shallow water corals have a stronger regulatory system than deep water corals because shallow corals receive more red light as well as more light at all wave lengths.

The total jest of the article I got was you cannot put all corals in the same bucket for lighting requirements. With a fairly flat spectrum some corals may do best between 60 and 300 PAR while others would do best between 250 and 1000 PAR under the same spectrum. In ideal situations you will match the spectrum that the corals normally receive in nature before they reach the trigger point where they naturally shut down from excessive light. This spectrum might be 12,000K light for some shallow water corals but for moderate to deep water corals it could be well beyond a 20,000K spectrum to the point the K scale is useless.

As I try to tune my lighting I look for the max peak in the 440nm to 460nm range. From there I want the intensity to drop in half for roughly every 10 nm I go below 440 nm and to 60 % of peak for every 45 nm above the 460 nm range with near 0 light above 640 nm.

However even this does not work for all corals as some that may require an extremely high PAR would require so much light that I could still be burning some of low light corals if you do create a proper mix of the corals.

 

[TropTrea]

The best reef tank lights are Halides. Many reefers are switching to L.E.D because of safety/heat, controllabillity, and not having to change the bulbs. If you look at all the succsesful reefers using L.E.D, who once used halides, most will tell you that the halides were only slightly better at growing corals, so so it's not worth switching back. You only have to look at the evidance to see that L.E.Ds work.

The big issue is the quality of the spectrum that the LED's are emitting. I believe LED's can exceed MH's if the spectrum is correct. Unfortunately there are to many LED fixtures out there with low quality spectrum's for the corals. Then the trick is to find which spectrum works best for the corals you are keeping. And even the so called expert Phd's that spent there life trying to figure this out will disagree.

Without consideration of cost there no no spectrum that could not be duplicated with a LED system. But the question is how much does one want to spend for a better spectrum when at a point you talking multiplying the cost for only a small percentage of gain. You can grow corals with a LED system that costs X dollars, bit one that costs 2xX dollars might grow corals 40% better, or 4xX could give you another 20% improvement, But for another 1-% it might cost you two or three times more.

 

[nynick]

This new idea that you can just cover the led with colored lenses is interesting though. I admittedly know next to nothing about it but I did read a little bit about it...seemed to be mainly from led producers however....

Anyone here that is more familiar with this?

 

[DiscusHeckel]

I thought this article may be of interest to some. It is about the impact of red light spectrum on S.pistillata. It is a heavy reading though ...

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0092781

 

[TropTrea]

This new idea that you can just cover the led with colored lenses is interesting though. I admittedly know next to nothing about it but I did read a little bit about it...seemed to be mainly from led producers however....

Anyone here that is more familiar with this?

I have seen several articles on it and it seems like a new technology based on an old one. The efficiency of these systems seem to vary considerable. However I have not seen any made by a LED manufacturer but instead by a second or even a third party.

The basic technology seems to closely related to some light refractory system. Where if you change the angle of the light of the resulting wave length will change.

 

[TropTrea]

I thought this article may be of interest to some. It is about the impact of red light spectrum on S.pistillata. It is a heavy reading though ...

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0092781

This almost sounds like a shorter version of the paper I original read on this subject and referred to earlier. Slightly different wave lenghts were used between these experiments and the one I originally red used different red wavelengths for comparisons. I believe the separately used 600, 620 640, 660, and 680 nm light sources. in the original. while for the blue light they used a wider spectrum blue between 430 and 470 nm. They ran the lights at an identical PAR total but varied the ratios of red to blue on the first run of experiments, then when determines 3 considerably different ratios from there original results started trying various PAR levels on those ratios.

If I remember correctly they found a ratio of 95-5 blue to red as the best for the different corals they tests. But the ideal PAR varied between the different corals on there next experiment.

 

[nynick]

Interesting, sounds a little more advanced than I had it in my mind. (think colored xmas lights )

Btw, when I wrote articles by "led producers" what I really meant was the guys who make these things, not the actual led's. Needless to say they were all proclaiming the second coming of Christ.

 

[Fredfish]

This almost sounds like a shorter version of the paper I original read on this subject and referred to earlier. Slightly different wave lenghts were used between these experiments and the one I originally red used different red wavelengths for comparisons. I believe the separately used 600, 620 640, 660, and 680 nm light sources. in the original. while for the blue light they used a wider spectrum blue between 430 and 470 nm. They ran the lights at an identical PAR total but varied the ratios of red to blue on the first run of experiments, then when determines 3 considerably different ratios from there original results started trying various PAR levels on those ratios.

If I remember correctly they found a ratio of 95-5 blue to red as the best for the different corals they tests. But the ideal PAR varied between the different corals on there next experiment.

With all the stuff you have posted here, I would love to get my hands on that paper.

 

[TropTrea]

With all the stuff you have posted here, I would love to get my hands on that paper.

I wish I could post a link to it. However I'm very unorganized with keeping track of links to articles in any order and ocassional clear out my links. I will say that cam acorss it by clicking on a reference to another article I was reading which often turns out for me to long reading process.

I find a good article and get more curious about something that was in the article. So I go down to there reference section and start clinking on there reference data to create the article. From there it sometimes turns into a long chain of article after article digging deeper and deeper into a subject.

I got into this habit when I was doing research for a large corporation. We had two intern's in my area which had there job of finding things on the web that could relate to our project. When the found something they would send one of us the links to evaluate if there was anything useful in it. If you spend enough time on the web you would shocked what you can find.

Overall on coral lighting I would say this is fairly new field that has been studied in detail until the last few years. The ability to create narrow spectrum LED's today is something that is drastically starting to move the field forward. Research from 10 years ago was limited to using various K bulbs and filters but today any spectrum imaginable can be created. The only real limitations today exist in funding for this type of research.

 

[Fredfish]

I wish I could post a link to it. However I'm very unorganized with keeping track of links to articles in any order and ocassional clear out my links. I will say that cam acorss it by clicking on a reference to another article I was reading which often turns out for me to long reading process...

That sounds awfully familiar.

 

[conix67]

I have seen several articles on it and it seems like a new technology based on an old one. The efficiency of these systems seem to vary considerable. However I have not seen any made by a LED manufacturer but instead by a second or even a third party.

The basic technology seems to closely related to some light refractory system. Where if you change the angle of the light of the resulting wave length will change.

Do you have links related to this topic? As far as I know, it's next to impossible to change the light spectrum. The only method to get other colors is through a filter (subtractive) or prism (through refraction) or phosphor (florescence?).

 

[mussel and hate]

If they were from that site that we can't talk about then I don't have high hopes. I was skeptical from the start as the chips lenses appear slightly cloudy from the get go........

They probably are from the same vender zachts. It'd be nice if we could share important information like this but I guess community isn't as important as sanctions against an external entity.

I have the new smaller form factor TV stars installed and running for a couple months now, I haven't seen any degradation of the primary optics yet. I'd expect to see them on the lower frequency diode first as that is what happened with the older style. The HV emitters optics burned at a much slower pace. I guess I'll just bide my time and observe.

 

[zachts]

They probably are from the same vender zachts. It'd be nice if we could share important information like this but I guess community isn't as important as sanctions against an external entity.

I have the new smaller form factor TV stars installed and running for a couple months now, I haven't seen any degradation of the primary optics yet. I'd expect to see them on the lower frequency diode first as that is what happened with the older style. The HV emitters optics burned at a much slower pace. I guess I'll just bide my time and observe.

the problem continues to be true ultraviolet light below 400nm. emited in small amounts by "violet" LEDs but when it is concentrated and focused thru a plastic or other material not UV stable then the degradation happens very fast.

 

[TropTrea]

the problem continues to be true ultraviolet light below 400nm. emited in small amounts by "violet" LEDs but when it is concentrated and focused thru a plastic or other material not UV stable then the degradation happens very fast.

Yes I will partly agree. But interestingly this never happened to me using so called 410 and 420 nm LED's. It only hit me with the 430 nm LED's. There is a possibility that the 430nm have a broader spectrum which extends more below 400 nm but this I doubt. My doubts are based on some spectrum someone posted on a another thread here where they did a comparison of several LED's in the near UV or violet range. Interestingly he showed difference between them but if you were to sort the LED's by spectrum and compare it to the claimed peak frequency some appeared considerably out of the advertised range.

 

[TropTrea]

As far as I know, it's next to impossible to change the light spectrum. The only method to get other colors is through a filter (subtractive) or prism (through refraction) or phosphor (florescence?).

this was true before the LED's started to be made in a wider selection. If you go through the maufacturers pages for Cree and Phillips you will find that if you select the proper bin numbers with your orders you can get pretty much any wave lenght LED you desire from 445nm on up to 690nm. With banks of various colors you can very the intensity of any of these individually or in groups controlling the spectrum. These methods are even more accurate than filters.

It is like a said earlier dependent upon how deep the budget is for the individual or group doing the research. Trying to get some of specific wave length LED can get fairly expensive as I had located some quality led's in specific wave lengths but the price for a single unmounted LED was over 10 times what I usually pay for a any mounted LED''s.

I have seen research facilities that could spend $25,000 without batting an eye for some experiments when they have the right sponors for the programs.

 

[conix67]

this was true before the LED's started to be made in a wider selection. If you go through the maufacturers pages for Cree and Phillips you will find that if you select the proper bin numbers with your orders you can get pretty much any wave lenght LED you desire from 445nm on up to 690nm. With banks of various colors you can very the intensity of any of these individually or in groups controlling the spectrum. These methods are even more accurate than filters.

It is like a said earlier dependent upon how deep the budget is for the individual or group doing the research. Trying to get some of specific wave length LED can get fairly expensive as I had located some quality led's in specific wave lengths but the price for a single unmounted LED was over 10 times what I usually pay for a any mounted LED''s.

I have seen research facilities that could spend $25,000 without batting an eye for some experiments when they have the right sponors for the programs.

You don't get wavelength from 445nm to 690nm from just binning LEDs. Different wavelengths are achieved by using different types of semiconductor material. The binning applies due to the fact that the controlling the quality of the semiconductor material is difficult. There's a reason high powered UV LEDs are substantially pricier than blue LEDs, because they use the material that's more expensive, or yield is lower.

The only practical way to produce other light spectrum given a single light spectrum source is through phosphors which is also widely used by florescent lamps including T5s. However, using phosphor cannot change the entire light output into another spectrum either, and the efficiency drops significantly.

If you add banks of various colors, you're adding various light spectrum to create different overall color temperature (12000K vs 15000K, etc). It still does not change the color spectrum from individual color sources.

 

[zachts]

Yes I will partly agree. But interestingly this never happened to me using so called 410 and 420 nm LED's. It only hit me with the 430 nm LED's. There is a possibility that the 430nm have a broader spectrum which extends more below 400 nm but this I doubt. My doubts are based on some spectrum someone posted on a another thread here where they did a comparison of several LED's in the near UV or violet range. Interestingly he showed difference between them but if you were to sort the LED's by spectrum and compare it to the claimed peak frequency some appeared considerably out of the advertised range.

Never once had problems with Rapid LED's Chips and those published graphs go down to near 400nm. Even the Old button style I've had running now at near full power for almost 3 years now.

It's still a problem with the material used and the construction of the chips. Rapid has always carried a slight premium price tag and there is a darn good reason. Quality materials! Steve's LED now uses the right stuff also, but so far no one stocking the 430nm that I've used as paid that much attention to detail. They also seem to have a broader spectrum from the few limited graphs I've seen but it doesn't extend particularly low compared to the 410/420nm that Rapid Sells which looks more like a 405 if you ask me........

 

[zachts]

The only practical way to produce other light spectrum given a single light spectrum source is through phosphors which is also widely used by florescent lamps including T5s. However, using phosphor cannot change the entire light output into another spectrum either, and the efficiency drops significantly.

It can ie, PC amber. Just a Royal Blue with only a heavy dose of yellow phosphor. brighter and more efficient than non phosphor based amber LEDs but a bit wider spectrum (Steve's LEDs sells these now). any color could be made this way but not much use for them. Personally I'd love to get a hold of a phosphor converted 540-550nm chip but no one makes them as there is no market and they would be crazy expensive as the phosphor needed to make the narrow range that would be useful reef lighting is one of the most expensive, next to far red phosphors.

 

[Fredfish]

...Steve's LED now uses the right stuff also, but so far no one stocking the 430nm that I've used as paid that much attention to detail...

If I understand correctly it is the quality of the dome lense over the LED that is the issue. A treated lense (or lense material) is required?

From the reading I've done on the Luxion Z they get around this entirely because the chip no longer requires a focusing lense. Near as I can tell it has something to do with the emmiter not letting photons out at a shallow angle of incidence? I'm wondering when we will see more of these available.

 

[conix67]

It can ie, PC amber. Just a Royal Blue with only a heavy dose of yellow phosphor. brighter and more efficient than non phosphor based amber LEDs but a bit wider spectrum (Steve's LEDs sells these now). any color could be made this way but not much use for them. Personally I'd love to get a hold of a phosphor converted 540-550nm chip but no one makes them as there is no market and they would be crazy expensive as the phosphor needed to make the narrow range that would be useful reef lighting is one of the most expensive, next to far red phosphors.

Can you post link to the technical spec on this LED? I'm not aware of any product (LED or not) that is able to convert entire light output into another light spectrum. Typical LEDs with phosphors are white ones, and it simply converts part of the blue to others providing white look to it.