# Led DIY



## medlight (28 Dec 2021)

I have been working on DIY led screens for a long time, I have always had very good results with them, two years ago for changing I acquired two vivid 2 chihiros, and the truth is, they are powerful, but they do not finish convincing me as to the response of the plants and we are talking about two screens for a surface of 100 * 40 * 40 in height, I think the spectrum is weak anyway and after all we are talking about three monochrome. so I have decided to create a study of what will be my new configuration to create.
The materials will be of good quality XPG-2-S4, Semiled, Bridgelux, Epiled.


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## Aquahorti (29 Dec 2021)

A couple of suggestions for your project:

1.
 It seems to me like you have fallen into the pit of trying to get a spectral power distribution that fits your needs by mixing LEDs with fairly discrete wavelength output. Why not go with one of the better white LEDs on the market and then suplement the spectral power distribution up where you feel you need to do so?
 I do not have any experience with any of the brands you mentioned, and after having looked them up and the specs, the only one that really made a positive impression is the Thrive98 LED from Brigdelux. I noted that most of them seems to run pretty hot and that will in turn reduce both lifetime and efficacy. I assume this is due to the lens they have, as that will help generate more heat on the LED itself (transmission of the light and reduced airflow over the LED).
 With regards to the Thrive98 I would like to point out that I am a bit unsure about the spectral power distribution they present,  as the y-axis does not have clear divisions on it and I can’t get to be perfectly normalized. That being said I would assume that using a Thrive98 (provided the spectral power distribution is correct) and suplement it with some discrete LEDs at 730 nm and 400-405 nm (or even 380-385 nm) would make for a pretty nice array.


2.
 Why the extra 730 nm? yes it helps with photosynthesis, mainly as a booster, but it can also make the plants more leggy and adding to much would probably not be helping you get the look you are after, unless that is leggy plants you are after. I do not use any extra in the 730 nm range, as I like my plants more compact, but I still have an intensity in the 730 nm range around 20% of the peak intensity. I know there are different results from research on this, but I am going with moderate levels in the IR range.

3.
 The different white LEDs, are they for simulating sunrise and sunset? And if so have you seen an actual benefit in plant response to it? I have used it in the past but have come to the conclusion that if there are any benefits they are so small that it is not worth the efford.

4.
  More of a comment to your take on the RGB lights. I 100% agree with you, I see RGB lights as a misguided fad.

As a help to some I’ll add a link to a presentation from 2018 regarding the spectral power distribution, plant response and requirements, and why PAR is really not a good metric with the knowledge we have gained over the last couple of decades: https://fhi.nl/app/uploads/sites/32/2018/11/Alcom_LED.pdf.
It is easy to read presentation, with a couple of links that will be more aimed at scientifically minded people.


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## jaypeecee (29 Dec 2021)

Hi @Aquahorti 

I just want to thank you for the attached presentation, which I found very informative.

I have a question for you - to what extent is horticultural* lighting applicable to the aquarium environment? I ask because I've watched several video presentations by Dr Bruce Bugbee (Apogee Instruments). In one of the videos, he says something on the lines of - blue light shrinks plants. But, most of his research appears to be in the field of crop plants. So, does blue light shrink submerged aquatic/aquarium plants?

Thanks in advance.

* As your User Name is Aqua_horti,_ I assume your work is in the field of horticulture?

JPC


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## medlight (29 Dec 2021)

Aquahorti said:


> A couple of suggestions for your project:
> 
> 1.
> It seems to me like you have fallen into the pit of trying to get a spectral power distribution that fits your needs by mixing LEDs with fairly discrete wavelength output. Why not go with one of the better white LEDs on the market and then suplement the spectral power distribution up where you feel you need to do so?
> ...


*1 I use these chips because the vast majority of high-performance commercial screens use them, with them I get power, in addition to being able to make them work at a low level, which means they emit little heat.
*2 I add very few of them in relation to other waves
*3 the whites only have the lighting function for the dime effects, Arduino is in charge
Good contribution I will take a look at your pdf. A cordial greeting


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## jaypeecee (29 Dec 2021)

medlight said:


> A cordial greeting


And to you too, @medlight.

Welcome to UKAPS!

JPC


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## Aquahorti (29 Dec 2021)

Hi jaypeecee,

I have no knowledge of blue light shrinking plants, but research have shown that light from 300 nm up to something like 430 nm will help the plants get more dry matter, that in turn will help them withstand external stresses. I guess (I have no basis for saying that this is the case) this could trigger something that would make the plants lower (pure speculation) but could be something like dry matter per stem vs growth time.
Good question though, and it will give me something to look into.

There so many mechanisms that kick in when plants go from emersed to submerged that it is hard to guess based on what you see in emersed growth. Just look at some of Ole Pedersens research (he is with Københavns Universitet and also works with Tropica. On top of that he does scape).

With regards to my nick:

Heh, no not at all, have a couple of degrees in Mathematics and Physics but nothing within the field of biology. I do like reading about research on plants, especially with regards to light as it ties back to one of my degrees in Physics and aquascaping as well. I does not make me an authority in the field in any way, I just like to read And expand my knowledge.
And work wise I have sold my soul to the dark side as I work in Oil and Gas.


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## medlight (29 Dec 2021)

jaypeecee said:


> Hi @Aquahorti
> 
> Entonces, ¿la luz azul encoge las plantas acuáticas / de acuario sumergidas?


For quite some time I have always read that the high spectrum in blue caused the stems to bend and it is certainly true, when I have subjected my tank to changes of tubes of 6500k by 10000kº automatically the plants shrinks , why? It is something that I never found information, every time there are less of the old school


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## Aquahorti (29 Dec 2021)

medlight said:


> For quite some time I have always read that the high spectrum in blue caused the stems to bend and it is certainly true, when I have subjected my tank to changes of tubes of 6500k by 10000kº automatically the plants shrinks , why? It is something that I never found information, every time there are less of the old school


That could be a function of the spectral power distribution. With the higher K rating you have less red wavelengths, and some research suggests that light around the 730 nm help plants grow longer stems. 
But again K rating of light really doesn’t tell us much about the spectral power distribution other than you have more light towards the blue or red for high and low K ratings.


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## Aquahorti (29 Dec 2021)

jaypeecee said:


> I have a question for you - to what extent is horticultural* lighting applicable to the aquarium environment?


Forgot to answer this question.

To the same degree that sunlight is applicable to plants that can thrive above water as well as under water. 
I know this is repeating myself from other threads, but if we focused more on having light that mimics natural sunlight, so that it is only the intensity we change, we would make our lives much easier. 
My experience is that growing plants in aquariums becomes a walk in the park. At home I use Yuji VTC series lights and my wife uses more traditional aquarium lights, and I can get away with cleaning the glass once every 1-2 months, where she needs to do it every 1-2 weeks.
I do have a couple of aquariums with traditional lights (Fluval Spec and ADA Solar II/ADA Solar Mini M) and they require much more cleaning as well. I will over time redo the lights in those setups as I do not find the extra cleaning required particularly fun.


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## Maf 2500 (29 Dec 2021)

I always took the studies on reaction to blue light to mean that deficiency of blue light causes stem elongation rather than excess of blue light causes shrinkage. 



> Generally, blue light suppresses extension growth; plants
> grown with blue light are usually shorter and have smaller,
> thicker and darker green leaves compared to plants grown
> without blue light


From https://www.canr.msu.edu/floriculture/uploads/files/blue-light.pdf

Of course sunlight always contains plenty of blue light, so natural outdoors growth might be considered to be growth in the presence of blue light.

Anyway, I look forward to seeing your DIY light when completed @medlight


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## Aquahorti (29 Dec 2021)

At Maf 2500.

Reading your link, the last section:

they have not been able to make consistant results in the greenhouse with regards to suppressing plant hight.

I would say there is need for further research and possibly tweek more parameters to eliminate other factors. Doesn’t mean they are not on to something.


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## oreo57 (30 Dec 2021)

Personal observation: In some stem plants high blue and low red content shrinks the length of internodes..
Hygrophila difformis is easily manipulated by blue light .
I suppose things like sword plants really have nowhere to go.

Many effects are species dependent.
As to using hort. "principals" to a planted tank isn't really err practical since many " targets" just don't apply.   Like maximizing dry weight with minimum energy useage. Sounds worthwhile but is it really?

About the only factor that is important is pigment production. Which regardless of spectrum can be stimulated by intensity and usually by any " blue" from 460 to 380nm (generalization).


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## jaypeecee (30 Dec 2021)

Aquahorti said:


> ...research have shown that light from 300 nm up to something like 430 nm will help the plants get more dry matter...


Hi @Aquahorti 

You've lost me there. What is meant by 'dry matter' in this context?

JPC


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## Maf 2500 (30 Dec 2021)

jaypeecee said:


> What is meant by 'dry matter' in this context?


Total mass of plant matter once dehydrated. Often used as a metric for total vegetative growth in horticultural experiments or trials.


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## Aquahorti (30 Dec 2021)

oreo57 said:


> Personal observation: In some stem plants high blue and low red content shrinks the length of internodes..
> Hygrophila difformis is easily manipulated by blue light .
> I suppose things like sword plants really have nowhere to go.



Correlation is not causation. 

You postulate that it is due to the high levels of blue light and low levels of red, but just like in the link that Maf 2500 gave, you can not say that based on the data. They had used a faulty test methodology where they changed two parameters at the same time, something people should have been tought in science classes, not to do (in Denmark that is 5’th grade curriculum). It might turn out that it is the blue levels that causes it or it might be the red levels. I am not saying that you have to prove what mechanism it is, but there is research done that can give us hints:
Red light and stem development https://www.frontiersin.org/articles/10.3389/fpls.2016.00480/full
Interaction of white, blue and red light in different quantities: Long-Term Effects of Red- and Blue-Light Emitting Diodes on Leaf Anatomy and Photosynthetic Efficiency of Three Ornamental Pot Plants


Personally I prefer looking at work done in the area, and gain inspiration from it to help me get better at obtaining the results I am after. Not guessing based on hunches.






oreo57 said:


> About the only factor that is important is pigment production. Which regardless of spectrum can be stimulated by intensity and usually by any " blue" from 460 to 380nm (generalization).




Let us just be clear on what is blue light. Blue light is defined as light between 400 nm and 500 nm, not 380 nm to 460 nm. UV-A is between 315 nm and 400 nm, so your range partly covers UV-A and blue light and thus it is not correct to use the term blue light about it. I have a link to an article about pigmentation in plants, and when it comes to light blue light is ranked 3’rd, after high white light (that also contains blue light) and UV-A in moderate levels. I can’t find the link right now but will post it once I get some time to look for it. So your above statement is just wrong.
UV-A and plant health: https://www.frontiersin.org/articles/10.3389/fpls.2019.01563/full

And I value healty plantgrowth over pigmentation that in some cases is detrimental to the plants health.


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## JoshP12 (31 Dec 2021)

Love it.

Each absorbed wavelength will yield a unique potential “growth” for the plant (dependent on if the photosystems etc are present for conditions given). Provided everything is there, the “growth” can happen. 

A nice thought through this thread for me has been to via McGree curve, consider the influence that wavelengths and combinations will have on nutrient demand. 

About a year ago, my co2 was a bit high for the fish so I shifted my lights to have more red and can't remember how long but next time I looked fish were fine - this in conjunction with a darker drop checker.

Understanding how the plant reacts to nutrient restrictions, if we can link wavelength to demand, we can predict plant forms. 

I’m thinking changing demand on co2 indirectly and influencing nodes/leaf size. But it’s not so simple as that —> likely morphology will be influenced by what is needed to capture and metabolize certain wavelengths and  to cope with different energies/conditions.

It’s too much!!!


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## erwin123 (31 Dec 2021)

I hope someone will actually do tests of near infrared and UV-B LEDs on aquatic plants to see if there is any difference. I'm following Dennis Wong's FB where he is testing out the Week Aqua P600 (with UV LEDs) but so far he has not mentioned anything (which suggests that the effect if any may be too subtle).


This page shows that NIR had opposite results with different terrestrial plants - if response to spectrum is so species dependent it may not be possible to draw any general conclusions : The Effect of Near-Infrared Radiation on Plants - All Things Lighting Association


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## oreo57 (31 Dec 2021)

Aquahorti said:


> Correlation is not causation.
> 
> You postulate that it is due to the high levels of blue light and low levels of red, but just like in the link that Maf 2500 gave, you can not say that based on the data. They had used a faulty test methodology where they changed two parameters at the same time, something people should have been tought in science classes, not to do (in Denmark that is 5’th grade curriculum). It might turn out that it is the blue levels that causes it or it might be the red levels. I am not saying that you have to prove what mechanism it is, but there is research done that can give us hints:
> Red light and stem development Spatiotemporal Phytochrome Signaling during Photomorphogenesis: From Physiology to Molecular Mechanisms and Back
> ...


Def of uv is artificial and actually variable .


> Ultraviolet (UV) light falls in the range of the EM spectrum between visible light and X-rays. It has frequencies of about 8 × 1014 to 3 × 1016 cycles per second, or hertz (Hz), and wavelengths of about 380 nanometers (1.5 × 10−5 inches) to about 10 nm (4 × 10−7 inches).











						What Is Ultraviolet Light?
					

Ultraviolet light is a type of electromagnetic radiation. These high-frequency waves can damage living tissue.




					www.livescience.com
				




None of this is peer reviewed science. No need for real exact definitions.
Not going to defend  my circumstantial evidence though and yes I am well aware of the concept of correlation is not causation but my " observations " follow general principals.
And keep in mind even well documented experiments on " plant a" means nothing to " plant b"......








						LEDs: Blue & Far-Red Light
					

4/1/2019 Yujin Park & Erik Runkle




					www.growertalks.com
				




Except for people there is not a single organism on earth that could probably tell the difference between 400nm (blue) and 399nm(UV by "some" definitions) light..

500nm is also not blue by Hunt's definition...I have no idea who Hunt is btw.. 








						Spotlight - Product Review: Neptune Systems SKY LED Luminaire
					

Neptune SKY Led Light Product Review




					www.reef2reef.com
				





> I used terminology found in Hunt's book on light.





> *Definitions of Spectral Bandwidths: *Since there is a gradual transition between colors in the spectrum, it is not surprising that definitions of bandwidths vary among reference sources. These are as used for this report: UV-A: 350-399nm; Violet: 400-430nm; Blue: 431-480nm; Green-Blue: 481-490nm; Blue-Green: 491-510nm; Green: 511-530nm; Yellow-Green: 531-570nm; Yellow: 571-580nm; Orange: 581-600nm; Red: 601-700nm. Technically, the red portion of the spectrum should be reported as that radiation of up to about 750nm, but most quantum meters report to only 700nm. Apogee Instruments has released a ‘ePAR’ quantum meter that extends further into the absorption range of P700 found in Photosystem I.


Really the use of any "color index" just adds to confusion.. Things should be determined by energy level ranges regardless of where it ends up on a color spectrum.


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## oreo57 (31 Dec 2021)

and..for fun








						Light signaling and plant responses to blue and UV radiations—Perspectives for applications in horticulture
					

Ultra-violet (UV) and blue radiations are perceived by plants through several photoreceptors. They regulate a large range of processes throughout plan…




					www.sciencedirect.com
				

















						Difference in the action spectra for UVR8 monomerisation and HY5 transcript accumulation in Arabidopsis
					

The photoreceptor UV RESISTANCE LOCUS 8 (UVR8) activates photomorphogenic responses when plants are exposed to ultraviolet-B (UV-B) light. However, whereas the absorption spectrum of UVR8 peaks at 280 nm, action spectra for several photomorphogenic UV-B responses show maximal photon...




					pubs.rsc.org


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## jaypeecee (31 Dec 2021)

Hi @Aquahorti & @oreo57

Thanks, guys. Much food for thought here. I am looking forward to spending some time absorbing your comments.

JPC


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## erwin123 (1 Jan 2022)

I guess agriculture/horticulture every cent accounts and improving yield by 1% might make all the difference to the profit margin. 

But all I want to know is how to turn my Rotala Wallichii pink  If I could avoid increasing _overall _light intensity and instead simply increase the intesnity of certain spectrum (or maybe use UV, NIR bulbs) to do it, then that would great because then I would be using the least energy possible to achieve the desired effect - as opposed to the blunt instrument of maxxing all R/G/B with consequent risk of algae blooms.


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## oreo57 (1 Jan 2022)

Chasing red can be a challenge.
It isn't always light. Sometimes genetic.
Sometimes environmental.








						Nitrate Limitation: how does it make red plants redder?
					

Does low nitrate make aquarium plants redder? Nitrate limitation is the term used by advanced aquascapers to describe the strategy of unlocking the deeper reds in selected plant species that respond well to those conditions. Not all aquarium plants get redder due to low nitrates, but many...




					www.2hraquarist.com
				




Never forget photoshop either or that one needs red light to reflect back red.


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## medlight (1 Jan 2022)

This is the spectra result of my configuration


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