Lighting spectra, Photosynthesis, and You

[jedimasterben]

This is awesome. Great find Squamosa. Only wish it had Luxeon-M diodes in it (so I could more accurately recreate my ATI Powermodule).

Just select a Philips Rebel diode and put in the radiometric or luminous output of the Luxeon M in its place.

 

[mcarroll]

Here is some Japanese software posted By Koji Wada on his facebook site, enabling the blending of different wavelengths of light based on the spectral absorbances of different coral pigments.

SPECTRA

I finally got around to playing with this a little. Definitely interesting. Thanks for posting!!

I'm having a blast on the "Irradiance in the Reef" graph trying to see what it would take to emulate 20 meters' depth. The first thing that's apparent is how few red emitters (none)....and how few daylight...(<3% of emitters so far, and getting less as I fill out the blues-and-lower). In fact, there's more green than any other wavelength. Together, green and cyan dominate the list, so far:

• LED Violet (420nm) [120°] x19
• LED RoyalBlue (450nm) [120°] x11
• LED Blue (460nm) [120°] x15
• LED Blue (470nm) [120°] x5
• LED Blue (480nm) [120°] x31
• LED Cyan (500nm) [120°] x40
• LED Green (530nm) [120°] x28
• LED Green (540nm) [120°] x28
• LED Amber (580nm) [120°] x8
• LED CoolWhite (8000K) [120°] x5

Its system of "!" alerts in the "Synthetic Spectrum with Spectrum Adviser" could perhaps be slightly misleading since my DIY white:blue fixture "scores" so poorly, yet grows corals so well. Still interesting if you just take the info for its stated meaning and don't apply its conclusions too directly to your tank. "!!!" does not equal "need" in other words. (I have no idea what the author's intentions were, so maybe this is all obvious and intended/expected.)

Also, even though it does apparently have an input for lens angle and height of emitter from the water, it's not clear whether or how these affect the charts. Seems to have no effect on the "Synthetic..." chart, but works more-or-less as expected on the "Irradiance..." chart.

Anyway....still having fun noodling with it!

 

[mcarroll]

dinoflagellate called zooxanthellae that performs photosynthesis, providing the coral with energy (but does not fill the corals needs 100%, only energy, all corals need to be fed, but that’s another post for another day).

(From the first post.)

It's a reference from 1968 so it's not too surprising I guess, but that statement is out of date. Dino's and corals share everything, including nutrients - much, much more than was realized and not just energy. (Will post up a link if I can locate one.)

https://www.reef2reef.com/forums/showthread.php?t=164651

Link number seven in the list...section on symbiosis.

 

[mcarroll]

Thought this (also very old) data might be interesting to some:

Figure 2.6(a) depicts the spectral dependence of the radiance of submerged sandy shoals and reefs as observed by Duntley (1963) looking straight down through a glass-bottomed boat surveying parts of the east coastof Florida. Radiances for the same submarine area observed from an altitudeof 4300 feet (1300 m) are depicted in Fig. 2.6(b).

Fig. 2.6. Relative radiances for various bottom types as measured lookingthrough the bottom of a glass-bottomed boat (panel a) and from an aircraft1300 m above the sea surface (panel b). [redrawn from Duntley (1963), bypermission]

Taken from Chapter 2 of Mobley’s , “Light andWater, Radiative Transfer in Natural Waters.â€

 

[mr.reeferman]

i have a question i never really looked into changing my lights and dont know much about lighting i have no corals running a fowlr system with the stock lights that came with the kit a petco but was wondering i have seen blue lights purple white etc what is the difference in the colors of the lights and what do they do for corals i am in china and aquarium equip is significantly cheaper here i want to start getting some coral when i arrive back in us and want to know whats best for my 29 gal tank nothing to pricy hopefully under 1000 yuan devide that by 6.8 to get the us price if anyone could help me out it would be greatly appreciated thanks and happy reefing to all

 

[arman]

I have been using 14000k metal halide lamp for one and ahalf year.Its time to change it up.The time i was using this lamp not only i had no problems but also i just bought corals like doughnuts that were going to die due to no reasons in less price and when i put them in my tank they just turn to be as good as they were at first.
But the only problem(if we call it a problem)was that the color of corals was not very attractive to the spectator.
Now what do you advise to me.
Should i change my lightning to LEDs or just have 14000k metal h and a row of LEDs including royal blue and violet and etc.????????????

 

[arman]

An other question is that is the frame of metal h lamps important or not????
Because ive made my own frame myself???????

 

[mcarroll]

I'd say go LED, but also consider starting your own thread cuz your post is buried in this thread and not 100% on-topic so you might not get that many lookers here.

 

[Pagey]

Here is some Japanese software posted By Koji Wada on his facebook site, enabling the blending of different wavelengths of light based on the spectral absorbances of different coral pigments.

SPECTRA

So this is awesome and I am in the process of doing up a DIY LED unit. Feeling much more confident now. I do have a drama I can't seem to solve.

1) I am getting an error under "Flourescent Proteins" unless I include a UV LED around the 390nm range.
2) I can't seem to find a chip in the 390nm range.

Has anyone solved this drama?

 

[Pagey]

G'day again guys.
Well I solved the 390nm LED drama. SemiLed do make a chip and I was able to find a retailer.
Now my drama is that I need to determine how hard to run my banks.
I did up a scenario on spectra with all banks at 100% and it looks like this. I set it up at 40cm (just under 16 inches) because that is how high I will mount these lights above the water surface. The tank's substrate will be approx 65cm below the water surface.
The light will spread evenly over a substrate area of 1.5 square meters by using a number of heatsinks...
I'm just not sure how the umol numbers and the irradiance numbers I am getting equate to real world par and ability to light corals. Does anyone have any idea about what they are seeing here? Thanks.

 

[mcarroll]

What you are doing here is great for tuning the colors relative to one another but to answer your current question about lighting the tank as a whole…brightness.

Get a lux meter. It is a very inexpensive way to directly answer your question for your self without any mysteriousness like this.

Obviously you are trying to replicate the levels of the sun which are well-known: shoot for between full daylight and direct sunlight levels.

You can find the scale on Wikipedia's lux article.

 

[FishRForMe]

Hello all. Some of you may recognize me from Nano-reef and my posts about LEDs, DIY recommendations, etc. Figured I'd post this up over here, as well. Putting it in general hardware and lighting because it applies to more than just LEDs.



With full-spectrum LED arrays becoming all the rage nowadays for better coloration, more and more people are considering them, but I see people saying all the time "dude, but corals only use blue light for all their energy and red only helps algae grow, ur an idiot if you add red light" (direct quote from one user). This is just not so.

Here is a paper called "Photosynthetic Pigments of Symbiotic Dinoflagellates (Zooxanthellae) from Corals and Clams" by S.W. Jeffrey and F.T. Haxo, 1968. You can find the PDF file here: http://www.biolbull.org/content/135/1/149.full.pdf

In it, there is a pretty staggering amount of in-depth information to read through. I’m going to sum it up and kinda generalize the best I can, so here goes!



Corals contain a colorful symbiotic dinoflagellate called zooxanthellae that performs photosynthesis, providing the coral with energy (but does not fill the corals needs 100%, only energy, all corals need to be fed, but that’s another post for another day). These contain pigments of certain colors that absorb light. The biggest players involved are chlorophyll a and chlorophyll c, peridinin, and neo-peridinin (notice no chlorophyll b, which is not present in zooxanthellae like it is in terrestrial and freshwater plants).

These are the bulk of pigments contained in most zooxanthellae (listed in order of highest population), their spectral maximas (the peak absorption wavelengths), and the color they reflect back. The wavelengths are essentially the average of what is presented in the article, with the range usually ~4nm or so. They were taken from many specimens, including Tridacna gigas, Tridacna crocea, Hippopus hippopus, Pocillopora sp., Amphidinium sp., and Peridinium cinctum.

[now, you might be wondering 'if these pigments are so colorful, why is it that when corals are starved of light and build up zooxanthellae numbers, why do they turn brown instead of, say, green or red? Well, zooxanthellae typically contain two or more of these pigments - what do you get when you mix blue-green and brick red? brown. ]


Chlorophyll a outnumbers chlorophyll c ten to one in zooxanthellae in corals, but in tridacnid clams, chlorophyll c is present at two-thirds chlorophyll a, making it much more prevalent. Peridinin and neo-peridinin constitute 77-84% of total carotenoids present and are considered true accessory pigments to chlorophyll, as they are always present alongside chlorophyll.


As you can see by the wavelengths provided above, violet and blue light makes up 100% of the carotenoid absorption maximas, but in chlorophyll, violet is the most important spectra, and red spectra is nearly as important as blue spectra. The bulk of photosynthesis comes from chlorophyll, so I’d think twice about not including red spectra in your lighting. This can be somewhat proven using good old metal halides – people always say “use 10K for growth, 20K for colorâ€, which makes sense, as a 10K bulb will have more red spectra than a 20K, which will emit nearly all of its energy in the 420-460nm range.


When it comes to LEDs, we can pick specific wavelengths we want to add. It started off with cool white (7-10,000K) and royal blue (445-455nm) (and some Chinese fixtures use cool blue instead of royal), and now we recommend to use neutral white (4-5000K) and royal blue, with full-spectrum fixtures bringing in deep red (660nm), cool blue (465-475nm), cyan (495-520nm), and true violet (400-430nm, so no UV).


After picking through this article, I'm convinced that royal blue is not nearly as critical to the growth of corals as we imagine, and put into our fixtures. Violet, deep red, and cool blue are the most important, in that order. That being said, most royal blue LEDs will touch on the higher violet peak of chlorophyll a, but not as strongly as a true violet LED will. This is one reason I prefer using Luxeon Rebels for my royal blues, as their peak is at 445nm, so closer to hitting chlorophyll a's peak than Cree XT-E that peak at 455nm. The violet LEDs I would use are split half and half - Steve's LEDs sells SemiLED chips that are 410-420nm, with the peak at 417nm - right on target! In addition, LEDgroupBuy has a new custom bin of violet (not sure what Milad is going to call it yet) that will be available for sale within one week, it registers its peak at 430nm, which hits the OTHER big peaks in violet!

I still recommend having neutral white and royal blue in a 1:2 ratio, but I think adding more cool blue and more violet is very beneficial. A word of caution on both - too much cool blue can give a Windex-like look to your water, and too much violet can very easily bleach your corals, so keep them on their own dimmable drivers! Since true violet LEDs hit such peaks within photosynthetic spectra, the PAR value they put out is great, but since they are so close to being ultra-violet, our eyes simply cannot see most of the light they emit, so they appear dim, which makes it easy to add more and crank them up because it's like you can't tell they're even on. I have firsthand experience with this, for the first several months of my tank I could not keep SPS corals, they would all bleach out within a week or two of putting them in the tank from what I now know was too much light, but as soon as I started turning my violet LEDs down, I was able to keep them. Then again, I was using 16x true violet at 700ma over a 55g. A bit overkill in comparison to the eight I would recommend to use now.



Hope that helps to shed a little light on the subject (pun intended ). If you have any questions or need any clarification, or advice on what LEDs you should use, let me know, and if you have anything you'd like to add, go for it.

Thank you... I've been looking for this information!

 

[james frantz]

Hello all. Some of you may recognize me from Nano-reef and my posts about LEDs, DIY recommendations, etc. Figured I'd post this up over here, as well. Putting it in general hardware and lighting because it applies to more than just LEDs.



With full-spectrum LED arrays becoming all the rage nowadays for better coloration, more and more people are considering them, but I see people saying all the time "dude, but corals only use blue light for all their energy and red only helps algae grow, ur an idiot if you add red light" (direct quote from one user). This is just not so.

Here is a paper called "Photosynthetic Pigments of Symbiotic Dinoflagellates (Zooxanthellae) from Corals and Clams" by S.W. Jeffrey and F.T. Haxo, 1968. You can find the PDF file here: http://www.biolbull.org/content/135/1/149.full.pdf

In it, there is a pretty staggering amount of in-depth information to read through. I’m going to sum it up and kinda generalize the best I can, so here goes!



Corals contain a colorful symbiotic dinoflagellate called zooxanthellae that performs photosynthesis, providing the coral with energy (but does not fill the corals needs 100%, only energy, all corals need to be fed, but that’s another post for another day). These contain pigments of certain colors that absorb light. The biggest players involved are chlorophyll a and chlorophyll c, peridinin, and neo-peridinin (notice no chlorophyll b, which is not present in zooxanthellae like it is in terrestrial and freshwater plants).

These are the bulk of pigments contained in most zooxanthellae (listed in order of highest population), their spectral maximas (the peak absorption wavelengths), and the color they reflect back. The wavelengths are essentially the average of what is presented in the article, with the range usually ~4nm or so. They were taken from many specimens, including Tridacna gigas, Tridacna crocea, Hippopus hippopus, Pocillopora sp., Amphidinium sp., and Peridinium cinctum.

[now, you might be wondering 'if these pigments are so colorful, why is it that when corals are starved of light and build up zooxanthellae numbers, why do they turn brown instead of, say, green or red? Well, zooxanthellae typically contain two or more of these pigments - what do you get when you mix blue-green and brick red? brown. ]


Chlorophyll a outnumbers chlorophyll c ten to one in zooxanthellae in corals, but in tridacnid clams, chlorophyll c is present at two-thirds chlorophyll a, making it much more prevalent. Peridinin and neo-peridinin constitute 77-84% of total carotenoids present and are considered true accessory pigments to chlorophyll, as they are always present alongside chlorophyll.


As you can see by the wavelengths provided above, violet and blue light makes up 100% of the carotenoid absorption maximas, but in chlorophyll, violet is the most important spectra, and red spectra is nearly as important as blue spectra. The bulk of photosynthesis comes from chlorophyll, so I’d think twice about not including red spectra in your lighting. This can be somewhat proven using good old metal halides – people always say “use 10K for growth, 20K for colorâ€, which makes sense, as a 10K bulb will have more red spectra than a 20K, which will emit nearly all of its energy in the 420-460nm range.


When it comes to LEDs, we can pick specific wavelengths we want to add. It started off with cool white (7-10,000K) and royal blue (445-455nm) (and some Chinese fixtures use cool blue instead of royal), and now we recommend to use neutral white (4-5000K) and royal blue, with full-spectrum fixtures bringing in deep red (660nm), cool blue (465-475nm), cyan (495-520nm), and true violet (400-430nm, so no UV).


After picking through this article, I'm convinced that royal blue is not nearly as critical to the growth of corals as we imagine, and put into our fixtures. Violet, deep red, and cool blue are the most important, in that order. That being said, most royal blue LEDs will touch on the higher violet peak of chlorophyll a, but not as strongly as a true violet LED will. This is one reason I prefer using Luxeon Rebels for my royal blues, as their peak is at 445nm, so closer to hitting chlorophyll a's peak than Cree XT-E that peak at 455nm. The violet LEDs I would use are split half and half - Steve's LEDs sells SemiLED chips that are 410-420nm, with the peak at 417nm - right on target! In addition, LEDgroupBuy has a new custom bin of violet (not sure what Milad is going to call it yet) that will be available for sale within one week, it registers its peak at 430nm, which hits the OTHER big peaks in violet!

I still recommend having neutral white and royal blue in a 1:2 ratio, but I think adding more cool blue and more violet is very beneficial. A word of caution on both - too much cool blue can give a Windex-like look to your water, and too much violet can very easily bleach your corals, so keep them on their own dimmable drivers! Since true violet LEDs hit such peaks within photosynthetic spectra, the PAR value they put out is great, but since they are so close to being ultra-violet, our eyes simply cannot see most of the light they emit, so they appear dim, which makes it easy to add more and crank them up because it's like you can't tell they're even on. I have firsthand experience with this, for the first several months of my tank I could not keep SPS corals, they would all bleach out within a week or two of putting them in the tank from what I now know was too much light, but as soon as I started turning my violet LEDs down, I was able to keep them. Then again, I was using 16x true violet at 700ma over a 55g. A bit overkill in comparison to the eight I would recommend to use now.



Hope that helps to shed a little light on the subject (pun intended ). If you have any questions or need any clarification, or advice on what LEDs you should use, let me know, and if you have anything you'd like to add, go for it.

So I have a 14 gallon BioCube. It came with compact fluorescent blue and white. All I keep in my Cube or corals with a shrimp and an emerald crab. Seems that a lot of my corals are losing their coloration. I'm not really wanting to change over to LEDs what do you recommend did I get for my compact fluorescent. It is time for me to change my bulbs anyway

 

[fab]

You need to get to PAR. LUX measurements do not provide you the information you need for understanding the effects of your light on your plants and corals.

LUX is an intensity measurement for light that people see and the way people see it. LUX measures light that is subjected to a filter that is shaped to match how well we see light at different wavelengths. Our vision at the two ends of the spectrum, blue and red, is very weak. We see best in the green region, halfway between blue and red. It requires a very strong blue light for us to see it but we can see a very weak green light.

PAR measures light without that filter that matches human color perception because plants and coral agae benefit from (see) all wavelengths equally.

To convert from LUX to PAR is non-trivial as it requires wavelength by wavelength knowledge of the sensor's characteristics and calculations at each wavelength.

Unfortunately PAR meters are more expensive than LUX mrters, but LUX meters are useless for what we need for plant husbandry. It only serves to confirm what we see with our naked eyes, brightness. We need to "see" food value.

This link may help you. It is not a full answer but is a start.

http://www.apogeeinstruments.com/conversion-ppf-to-lux/

This next link, below, is excellent for understanding PAR, also referred to as PPF or as PPFD. With this link, scroll down to "Quantum Meters".
Watch the two videos, top one first.
http://www.apogeeinstruments.com/knowledge-base/

Together they are as good an explanation as I have seen for clarifying PAR in reasonably lay terms.

I hope this helps move you along an up the learning curve a bit.

fab

 

[mcarroll]

You need to get to PAR. LUX measurements do not provide you the information you need for understanding the effects of your light on your plants and corals.

A PAR meter is nice, but you're assertion of necessity is incorrect. A theoretical assessment.

You need do nothing more than check some of the threads you will find by searching the forum for "lux meter". The discussion has been had plenty of times, you can see plenty of people using them successfully.

Unfortunately for PAR meters, they are expensive which places them out of reach of 90% of all reefers.

They are more accurate by a percentage. However the mistake is to think they give a perfect representation.

Consumer level PAR meters are no more perfect nor any less usable than a consumer level lux meter so far as reefers are concerned.

The focus needs to be on how bad our eyes are at assessing relative intensity like this....absolutely terrible. Our brain literally works against assessments like that, always trying to normalize the image across all intensities in our brain.

The worst (still functinoal) lux meter is probably thousands of time more reliable than an eyeball assessment. Maybe as important as any other aspect of measurement, the lux meter's measurements are eminently repeatable.

It's crucial to think about what we're really doing...our actual use case.

For most people in this hobby, that use case is either dialing in new lights for a brand new tank, or for a system that's being converted from different lights.

A $free lux meter app for your smartphone (once verified as working properly) can get that job done.

A $15 handheld lux meter makes it nicer in every way. This is what I've been using for a few years now - successfully I'll add.

You can get a $75 lux meter with a submersible sensor, but measuring underwater is not a requirement for this use case.

Beyond the $75 level, you have to spend around $400 if you really hold out for a PAR meter.

I'm fine if you wanna save up $400 for a PAR meter. But going without a light meter of any kind whatsoever unless it's a PAR meter under these terms is kinda senseless. Isn't it?

One caveat: If you're building your own LED system that is sufficiently large (i.e. expensive) and aren't following a known pattern, it could be worth the expense of a PAR meter to get that extra accuracy - it's very possible to select or combine a mix of LED's that are crap in that circumstance.

Most people are following a pre-tested DIY pattern or buying manufactured lights. That's why most people can use a lux meter just fine. (Well, that and the corals themselves only require so much accuracy...that's another story tho.)

 

[billw]

Beyond the $75 level, you have to spend around $400 if you really hold out for a PAR meter.

As another alternative, USB PAR sensors are available for about $195.

 

[mcarroll]

Sure...and the seneye, etc. Each offers their own advantage for the cost. I have nothing against any of them.

Problem is, I think most people who actaully need or are otherwise going to own an expensive (>$20) light meter already own one...and that leaves everyone else behind.

The lighting and beginner forums are still full of posts with questions that could be answered and disasters that could be avoided by use of a simple lux meter.

The point being not to overlook the $free or $15 option just due to some form of light-monitoring snobbery couched in a chlorophyl absorption curve.

*Everyone* should be able - at minimum - to measure their reef light's intensity to a useful degree. And either of the cheapie lux meters will work for that.

(In the same vein...it might be surprising to some how useful a handheld spectrometer can be. That Spectra tool is awesome, but it's theoretical. My spectrometer is rudimentary in function, but real. (It works!)

Tell me you can't discern which wavelengths are strong and which are weak and which are actuallly missing from this cool while LED:


That's a really cruddy photo (tough shot to get) of what I see through my Spectrometer...looks much more clear and defined in person.

 

[SantaMonica]

We like to use regular lux meters for our GEM5 lights because it's the relative output from one light to another, for from one distance to another, or from one angle to another, that matters.

Plus they are all pure 660nm par.

 

[David Engh]

So where is a good starting point? What would you suggest for a beginner to do when they jump in head first with out doing all that research? I read most of these articles now an am still not grasping what light to use for what corals? Most store owners I've talked to about this get all flustered an annoyed when I get into asking them bout this subject an just tell me to buy this or that light an you will be fine. So my question for you guys would be where to start t5 or led or a combo of both.

 

[David Engh]

May be stupid question but why can't I use a lot of natural sunlight along with leds or t5 to get the same spectrum? Would this give it more natural sustainability?