# understanding lighting frequencies



## Andrew Butler (28 Dec 2016)

I'm sure someone can help me (and probably a lot of other people) out here. Trying to understand the relationship to photosynthesis and lighting frequency.

To my understanding the 2 main elements of lighting and photosynthesis are Chlorophyll A and Chlorophyll B. They both have particular frequencies along the colour wavelength at which adsorption peaks (approx);
Chlorophyll A - 430 & 662 nm
Chlorophyll B - 453 & 642 nm

If I am to try and match lighting to the above does the frequency of the LED have to be exactly 430, if not how much either way do I have to play with?

which frequencies would allow me to leave that particular colour on at night to create a moonlight effect, if any?

I'm welcome to different opinions and people telling me I'm wrong, I look forward to input


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## zozo (28 Dec 2016)

Any white light vissible with the human eye grows plants  all these lights contain the spectrum we need between 400nm and 750nm.
So it actualy doesn't realy matter that much all white light contains the spectrum a plants need..
400 is more towards the blue and 750 more towards the red.





When we buy lights they are usualy commercialy graded in Kelvin color temp.. It seems between 6500k and 8500k have the best spectrum for growing plants and have the best aesthetic color in the way our eyes perceive it.  There are grow led lights for sale only containing +/- 450nm blue leds and +/- 730nm red leds and grow plants very well but this is not realy aestheticaly pleasing to look at.

For example a 2700k light we percieve more as yellow so it mainly radiates a light between the 550nm and 600nm it still contains the whole wavelenght as shown in the graph above but yellow and red will be most dominant. The higher the K value say 8500K the more we go to the blue spectrum 450nm the les yellow and red it will contain but it still does after all it is still a white light. 

When it comes to moon light effect above a tank any color can do, it is a matter of taste.. Personaly i like a very dim natural white color as most pleasing.  Something to think about when having lights on at night is the plants Light Compensation Point. But also this, if you stay in the plants compensation point you'll be far above a moonlight effect, so this also isn't realy a thing you need to measure or worry about so much. Depending on the luminous strenght of the leds above your tank dimming between 2% and 10% you will stay way bellow this point and don't need to worry.


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## Andrew Butler (29 Dec 2016)

I appreciate what you have said zozo but I would like to understand it a bit more scientifically. I also believe there are frequencies which are seen by the human eye which simply go to waste as far as the plants go. I'm looking at the more marine based LED systems where you can control individual colours in a puck and a lot of them are a lititle heavier on the blue or low end of the wavelength.
I could be wrong about everything but I did read some of it on Wikipedia so it must be right, Surely?


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## zozo (29 Dec 2016)

I'm sorry that i'm not the scientist you are looking for and it puzzles me a bit what you like to know or try to understand more specificaly. But indeed you are correct most of the white light as we perceive it goes to waste as far as the plant goes. You can grow plants under only red and blue leds, plants use this spectrum and it doesn't do much if nothing at all with the rest. As you see in the above graph 430nm is blue and 642nm is red and if you look at the led grow light systems only contain leds in this spectrum not to waste energy on light the plant doesn't use. 

But solely using this spectrum above a planted tank or in a room doesn't look eastheticaly pleasing.

Scientificaly seen, white light doesn't excist, white isn't a color. We (our eyes) perceive it as white but it is a mixture of different wavelenghts. Take for example warm white, we perceive it as a warm yellowish light lean more towards the red spectrum and cool withe leans more to the blue spectrum.
Take an RGB led only containing Red, Green and Blue, of all leds illuminate with the same output the invironmantal light will look as white to us as the centre of the bellow graph represents. If you dim only the blue leds and leave the red and green the invironmental light as we see it will turn more yellowish in color but still contains blue. If we dim the red it will turn into a blueish light. The green is what the plant reflects and there for green plants look green to us. 



 

That's light a bit in a nutshell.. 

I have no experience with using marine light setups for planted tanks..But in basic understanding these are not designed and not ideal for growing plants. But by experience i do not have a clue about it..


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## Andrew Butler (29 Dec 2016)

zozo said:


> I'm sorry that i'm not the scientist you are looking for and it puzzles me a bit what you like to know or try to understand more specificaly



Quite why a reaction like this is called for I'm unsure, I had thanked you for your help but was just looking for the science behind it. The reason I would like to understand it is I think it is a good idea to understand the theory when trying to put something into practice.

I'm looking for a light where I can leave a light (adjusted in colour and intensity) on low of an evening as a 'moonlight' to enjoy the fish shimmer and not effect plant growth and one where I can adjust the colours to suit both my eye and the plants. I don't know of a light aimed at the freshwater market that has quite this versatility whereas in the marine based market there is lots to chose from.

I'm not trying to educate you just put it how I see it; although corals photosynthesise like plants they use different frequencies along the spectrum to what a flowering plant does and again a green plant does which is what I'm trying to understand. The pucks on marine LEDs tend to be very heavy on the blues which you can simply dial down and ramp up the reds then adjust the intensity of the spectrum after you have it looking right. They are also in general a lot more powerful than the majority of lights aimed at freshwater use.

Out of curiosty What makes you say they are not ideal for growing plants?


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## markk (29 Dec 2016)

Hi Andrew,

It's worth pointing out that the economics and usage of reef versus planted tank LEDs are very different.

Reef tanks are mimicking shallow tropical reefs that require high intensity lighting. Most freshwater aquatic plants that we grow require much lower intensities. The perceived colour of a reef tank is also a moving feast - even in the wild the same coral will look different at different depths etc. There is no right and wrong. Plants on the other hand are green (mostly)- that's what we expect to see and a significant shift away from that looks unnatural. Add in the reefkeepers' desire to boost certain wavelengths to enhance certain colours or increase penetration to the deeper areas of the tank and you have fixtures that cost many hundreds of pounds, cater to multichannel control and emphasise efficiency.

The typical cost of a freshwater led fixture is probably £100-150. At this price point control units and associated software become a significant additional cost. Furthermore most aquascapers (for want of a better word) don't want any more control than sunset/sunrise and a master dimmer. 

As others have stated, most warm, neutral or cool white LEDs will tick all the right boxes in terms of powering plant growth (red and blue) and looking natural (green). It's a matter of personal preference which look you prefer. Your plants will adapt and grow regardless. The spread of emissions from a white led will also ensure other pigments are 'covered' as well.

Hence there is little incentive for most planted tank LEDs to offer control. Relatively costly and little demand. 

I'm sure there are options - kessil springs to mind or some of the bespoke US suppliers.

When I built my first planted led fixture, I spent a lot of time considering spectrums, wavelengths etc. I planned if nothing else to have some red LEDs for natural sunrises and sunsets. One US supplier even states that an hour or so of red light in the 'morning' significantly boosts plant growth.

In the end I simply went for cool white with all the intensity control provided by my own software. It works.

As far as a moonlight effect is concerned, search the forums for light compensation point. Generally speaking running your lights at 2-5% will give the effect you are looking for without driving plant growth.

Regards,
Mark


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## zozo (29 Dec 2016)

Don't worry i do not feel like you are trying to educate me..  and only would be thankfull if you can or do along the way. That's why we all are here i guess.. So in a way we are constantly educating eachother with sharing experiences if it is scientific or not.. Science is in our hobby a very helpfull guideline to understand partialy what we are doing.. But for a great deal especialy in biology science is also still more general accepted hyphotheses and theories and should not be seen as absolut facts. And this is something we constantly bump into with eachother and try to make the best out of it with all the different experiences we encounter.

For now i'm building my own led lights above my aquariums for over 2 years now and also tried to understand the science behind it. But relatively fast found out that the understanding of all the numbers and abbriviations and terms of candela. flux, lumens, mols etc. etc. do not help you that much if you do not have the proper and very expensive equipment to measure it. For this you would need par or flux meters, spectrometers etc. to find out what the specific light you buy compaires to the specs the vendor gives you.

Anyway after listening to this interview with Cara Wade an expert in growing plants under arteficial light i realized i was wasting energy on trying to understand it more than i already do and found out for myself. 
http://www.stitcher.com/podcast/art...d-aquarium-with-cara-wade-scapefu059-43548241

I'm also using a moonlight effect above all my 3 tanks for the greatest part of the night. Also played with colors and such but in the end the most natural look for me was using a very dim natural white. The nicest effect you (or beter say I got, since it is a matter of taste) can achieve is using a spot light for that. As said as long as you stay bellow the plants light compensation point you can use what ever light you want, what ever looks good to you. It wont be strong enough for the plant to do anything much with it anyway and will have no negative effect. So you do not need to think of the correct color from a plants perspective. And if you for example still are in the compensation point of most plants you probably will not perceive it as a moonlight effect because it will be way to bright. Light compensation points in plants differ in plant sp. hence we have easy and advanced plant sp. when it comes to light needs.



Andrew Butler said:


> Out of curiosty What makes you say they are not ideal for growing plants?


I think Markk explained it enough, i'm not a reefer, so i only can quote them who tried to grow plants under reef lights..


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## tmiravent (29 Dec 2016)

What a nice discussion!
I made also some experiments and search in light, here is my small contribution:

- Reef vs Fresh Water
reef can make use of wither spectrum, some corals only reproduce with specific wavelenghts (as far as i know)
Fresh Water can only use 'visible' spectrum, much easier and simple! 
i'm watching a discussion about the use UV in fresh water (some guy's say it's possible and have success) need to see more about this one...​- Power
light strength is crucial, you define where you want to play
there are a ways to look at, tropica divide in 3 categories (low, medium and high), other divide in 4 categories (low, medium, high and very high)
this table is not written in stone just a start point:





you can see here a relation with PAR vs LUX values​- Color of light
important for us, we like to have a beautiful aquarium with nice colors. The good color is a bit subjective...
for plant's it doesn't matter, they need to have the right amount of photons to do the work!!
you can use green house 'violet' lamps to grow but they don't lokk very nice in the tank... (but they will work)​- Other features
Sunrise, sundown and moonlight, very beautiful but not essential.
If it's important to you, go for it! For the aquarium plants is not crucial.
This features  are absent in commercial fixtures because they tend to be high expensive to implement...
For 'some' fish can be important.​- Some words on some fixtures
ADA rgb, simple and beautiful! 
Take a look at spectrum distribution. It look's much more saturated in real life.
It doesn't have a dimmer, moonlight or other stuff. It's ON and OFF. I believe we can give 'some credit' to the brand.
Watch carefully their videos, the measure light power with a LUX meter!
Brand's like ADA and Twinstar are using RGB led's for specific color rendition (maybe also a 'rgb' fashion issue).
They also use a diffuse to mix the colors which result in less shimmering and apparent less 'bright'.​- PAR vs LUX
I know that PAR is in the top word's to speak about light, but...
Par is a linear scale that scientist use to read light along the day (outside) where there is variations. Clever adaptation, easy to manipulate data.
LUX is a logarithmic scale, more difficult to manage, but with a analog relation to light nature, LOGARITHMIC!
ADA uses lux meters to manage light, and i believe we can use inexpensive LUX meters too, with success!
​Some links:
I made some test with light fixtures with Nuno Matos
https://www.ukaps.org/forum/threads...ar-values-for-led-fixtures.43178/#post-469533

A good explanation about light(a bit old but still very usefull)
http://tropica.com/en/guide/make-your-aquarium-a-success/light/

cheers,
Tiago


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## dw1305 (29 Dec 2016)

Hi all, 





Andrew Butler said:


> To my understanding the 2 main elements of lighting and photosynthesis are Chlorophyll A and Chlorophyll B. They both have particular frequencies along the colour wavelength at which adsorption peaks (approx);
> Chlorophyll A - 430 & 662 nm
> Chlorophyll B - 453 & 642 nm


It is like the others have said, plants can actually make use of nearly all white light. 

The main problem for freshwater aquatic plants is often access to CO2 (~1ppm in water compared to 400ppm in the atmosphere). If you have an imbalance between high light energy and CO2 availability you can end up with damage to the plant from the "spare"  energy that isn't utilised to form carbohydrates.

Another issue is that in fresh water we are only interested in the photosystems of the <"viridiplantae or chlorobionta">, the clade that includes most of the green algae and that, as you say, have chlorophyll a and chlorophyll b as their main photosynthetic pigments. Things are very different in reef aquariums where you have <"dinoflagellate zooanthellae">, with chlorophyll c, and encrusting coralline red algae (<"Rhodophyta">) etc.

Although the peaks are quite narrow the photosystems of the viridiplantae contain accessory pigments, and structures, that allow them to make use of a wider range of wavelengths of light than the peaks would suggest. You can get a spectrum for photosynthetically active radiation (PAR), which will look something like this (it came from a grow-light web-site, rather than a scientific paper).



 

If you want a more scientific run-through (I'm not a plant physiologist), <"The Photosynthesis Page - Govindjee"> at the University of Illinois, gives access to the full book of <"Rabinovitch & Govindjee: Photosynthesis">, and the <"Photosynthesis Web Resource">

cheers Darrel


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## Andrew Butler (29 Dec 2016)

Lesson learnt for the day; don't try to over complicate things!


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## dw1305 (29 Dec 2016)

Hi all, 





Andrew Butler said:


> don't try to over complicate things!


Pretty much, it would be really nice to know how things work, but you just can't cover everything. 

Reefers and grow your own "_Tomato_" growers are a great resource because they really care about light wavelength and intensity, and getting as much bang for their buck as possible. It isn't as important for us. 

Personally I just use whatever light I have to hand, if I have a lot of light (high PAR) I have a big plant mass with plenty of floating plants (with access to atmospheric CO2), less intense light fewer floaters etc. It works for me, because I just want plants and I don't really care which plants they are, I don't do aquascaping or aesthetics really.

cheers Darrel


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## Andrew Butler (30 Dec 2016)

Thanks for the input Darrel, (and everyone else)
I assumed that the freshwater side of things would be much in the way reefing is where people on the forums understand the scientific bit behind lighting but it seems not so much.
I simply can't find a light with the features I want in freshwater so was looking at saltwater units, I know if I turn the blues down and reds up along with overall intesity dialed down they will work - there are programs aimed at using some lights in freshwater and the wavelength spectrum of the ecotech xr15 freshwater is pretty similar and seems to cover the same parameters to ones aimed at reefing


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## ian_m (30 Dec 2016)

dw1305 said:


> grow your own "_Tomato_" growers are a great resource because they really care about light wavelength and intensity, and getting as much bang for their buck as possible.


Yes they are trying to get the maximum grams of product they can get per watt of power (ie £££), so strange spectrums that maximise this are used. A good start to maximise aquatic plant growth per watt would be to use high pressure sodium lamps, at say over 150 lumens per watt (exceeding most LED's' efficiency). The main issue is your plants would look cr*p. So choose the lights that make you plants look good, greens popping out, make fish stand out and ignore what spectrum produces maximal growth. As previously quoted plants will use what ever light you supply.


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## tmiravent (30 Dec 2016)

Just be aware of light power...

Typical PI curve [image from: http://www2.geog.ucl.ac.uk/~plewis/geogg124/modelling.html]




Examples with marine/reef: [image from: https://en.wikipedia.org/wiki/PI_curve]



You can see, reefs need a lot of light! The fun start's at 80PAR

Fresh water, fast plants! [image from: https://en.wikipedia.org/wiki/PI_curve]



These examples are fast growing plants, now imagine the 'low light' plants...

Cheers


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## Andy D (31 Dec 2016)

Andrew Butler said:


> I assumed that the freshwater side of things would be much in the way reefing is where people on the forums understand the scientific bit behind lighting but it seems not so much.



Hi Andrew, there are quite a few on here that understand the science they have just determined that in the main it is not something to get too technical over as 'most' lights do the job we need them for. I understand your request for a moonlight that does not stimulate growth but as Mark put it, most lights set to a low level will give enough light to view the tank but not enough light to stimulate growth as they will below the light compensation point.



Andrew Butler said:


> I simply can't find a light with the features I want in freshwater


 How about THIS.


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## dw1305 (31 Dec 2016)

Hi all, 





tmiravent said:


> These examples are fast growing plants, now imagine the 'low light' plants...


Now that is a useful post.





ian_m said:


> high pressure sodium lamps, at say over 150 lumens per watt


They are still the optimal lighting for commercial glasshouses.  A £60 <"600W HPS"> grow lamp will fry almost any plant, but might be what you need to keep <"_Ludwigia sedoides"> etc. _through the winter.

cheers Darrel


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## Andrew Butler (6 Jan 2017)

Sorry, I've not been online so haven't seen the responses



Andy D said:


> How about THIS.



how about what Andy?

I have took on board the information but I just am not coming across a lamp which is automatic in the sense it will reduce intensity at a certain time every day then power off before starting up again the following day.


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## Andy D (14 Jan 2017)

Andrew Butler said:


> how about what Andy?



If you click on the word THIS it should take you here:

https://www.lupyled.com/en/


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## Rabb.D (15 Jan 2017)

ligthing frequencies is the range output of the wavelength of the lighting as you know light vibrates within a spectrum of volatility within certain ranges for each nano mole of spectrum of which each spectrum has a different interpolar exceeding the manual frequencies of their wavelength volatility.

as for the photosynthetic part, nothing is more important than white light spectrum because it holds all spectrum of colour so you should not care about using fancy colour output when it comes to the growth of you plants...


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## Andrew Butler (15 Jan 2017)

Andy D said:


> If you click on the word THIS it should take you here:
> 
> https://www.lupyled.com/en/



DOH!

Looks like it's a bit out of my price range though


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## zozo (15 Jan 2017)

Andrew Butler said:


> I have took on board the information but I just am not coming across a lamp which is automatic in the sense it will reduce intensity at a certain time every day then power off before starting up again the following day.



It not in the lamp, it's how you controll it.. 
http://www.wifiledlamp.com/led-magical-wi-fi-rgb-wi-fi-rgbw-controller-with-c.html

 It's a 4 channel PWM controller with a wifi module.. There also is an equal Wifi controller around with 5 channels.. Depending on how much light you need or want, the nowadays top noch 12/24 volt SMD strips could be sufficient.. These controllers are designed to control smd of the shelf..

But with some nifty thinking and some diy these devices can be used to dim other drivers or lightsources as well.

It's a bit complicated to explain.. Lamps need drivers, drivers can be controllable than you need controllers.. The above thing is only the (remotely programable wifi) controller.

It all is still in the cradle..  Babies make a lot of small steps the first year and grow fast and the steps they make get bigger by the day.. who knows whats around a year from now.. A year ago this controller wasn't yet made, at least not with the wifi module and remote control app.


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