Green/Yellow/Red LED's

[coolfishy101]

Hello all,

I was wondering if we are looking at the Green/Yellow/Red spectrum of LED's the wrong way. Some seem to claim them as a new "gimmick" and are only good for growing nuissance algae. So far from many tanks people love LED's at the start but over time see a decline in health/color, claiming the narrow spectrum causing the problem. The raidion by ecotech includes a variety of colors for a full spectrum. And i was thinking that maybe that nuissance algae is beneficial in small amounts. In other words, we need the blue for the coral, and the green/yellow/red to grow enough algae (algae free floating in the water column that we can't see) to feed the corals and/or pods. With only a narrow spectrum that for example the AI units provide, it's like having a bubble king skimmer on a 20gallon. Water that is too clean leading to pale corals.

I also understand there are tanks proving successful with "narrow spectrum" LED's, we all know there are exceptions in this hobby.

Am I way off on this? I don't know how much RGB the whites supply in today's units. It just seems to me we may be a bit narrow minded when we look at spectrum vs. what the coral needs. All in all I believe we are in the right direction.

 

[Cptn Spaulding]

I've heard of a LED fixture that has green and red ones on it as well as blue and white. i was told by someone who gets the same enjoyment as i do when it comes to certain spectrums, and he said it also looks very fake. It is very true that with the LED lit tanks with blue and white bulbs in it that algal growth is very minimal compared to halides or T5s. I barely clean my glass off with my PAR38s on my 90 and the algae on the rocks grow much slower than before.

I, however have seen no ill effects from the narrow spectrum band in my corals. actually, everything looks even better than it did before in my 55 with a 4 bulb nova extreme fixture with UV bulbs in it, although the new tank was just set up 2 months ago so I'm not sure if that is enough time to show any ill effects. An open brain coral has gained 50% in size and colored up dramatically, and my sps have either bleached a bit from too much lighting and poor placement on my part or have pretty much returned to their former glory (as well as some zoa/paly frags).

I definitely understand where you're coming from, and I've thought this on numerous occasions before, but now I am fairly certain that at least for most corals the wide spectrum band is unnecessary and does cause more algal growth. There are pods galore in my tank, even with just LEDs, polyp extension has been better than ever, color has been great!

I think a big problem with LED's is human error and coral misplacement in the tank. Everyone is used to halides and fluorescents, where it's brighter in the middle of the bulb, where LED's with optics on them are spotlights, especially closer to the bulb, and people melt their corals and blame the LED's for it.

Anyone want to correct me if I'm wrong? I'm pretty familiar with LED's but I am no expert in wavelength frequency, and it is a fantastic question as well. thanks for asking! I'm excited to see what other people have to say

 

[Todd100]

I like the rgb ecoxotic model where you can chose about 15 different colors and their intensity by remote. (I don't own one but might buy it, after I figure out if I'm going to buy led or t5 for my tank)

 

[TundraGuy]

Go check out Beeker's 200DD I think it will answer your questions about color and leds.

 

[Neoferdina]

I think what people are missing about LEDs (and lighting in general for that matter) is that it depends not on what light the coral needs but what their zooxanthallae need. Sure, you corals may look awesome but they might be starving because the zooxanthallae are starving. Most algae (almost all plants for that matter) have a bimodal absorption spectrum; one peak in the red, the other in the blue (shifts a bit depending on which clade is present).

It's possible to grow plants under only red or blue lights but they will grow deformed (either long and leggy or stunted with huge branches). Give them the right mix of just these two colour and they grow like they are in steroids. Same goes with algae; without the whole spectrum of light they need they'll fall short of their growing potential (and along with it quantity, nutritional value and so on). You already have the proof for this; why do you think niussence algae explodes when you get too much red in your spectrum (i.e. Old lights)? Underwater, red light is filtered out first, so the spectrum is dominated by blue and red is limiting. Give it some red and everything will take off. This is why 10K lights will give better growth than 20K lights. One has more red (thus more PAR) than the other.

So what the manufacturers have done here is give you the tools to tweak your LED set up and to experiment to find what YOU and your corals find best. It's not there for your to pimp your colour to make the tank look like a disco ball. You only need a small amount of red light in there to keep everything happier, but if the red is unevenly distributed (like the tiny point source of an LED) it doesn't do much good other than growing algae is fairly specific areas of your tank.

The idea for the red LEDs is there and is correct. Implementation of this idea will take some time to figure out.

 

[wildman926]

One other thought about the lack of algae in the tank, is an excellent protien skimmer keeping the tank too clean. I know this thread is about led spectrums, but as stated above -"it's like having a bubble king skimmer on a 20gallon. Water that is too clean leading to pale corals", I feel skimmers should run part time, and not full time. I changed my skimmer to run 12 hours a day, 6 hours at a time, with the off period at night, 12 - 6 am, when they are feeding. I have seen a huge difference.

Water changes are absolutely necessary also. Quality salt mixes will contain what is needed for coral growth, and that is replenished during water changes.

It is the combination of lighting and water quality that keep the coral growth occurring.

 

[cbellm]

I am currently researching LED builds being as I am planning on a DIY here in about 6 months. I am a Bio nerd as well so I have been doing a lot of research on chlorophylls as well. I am certainly not an expert but the more I read the more I believe reds are a necessity.
If you look at the spectrums that most chlorophyll absorbs you see 2 major spikes one at 420-500nm (blue spectrum) and another at ~630nm (red) between these is the green spectrum which is not being absorbed and therefor reflected (hence the reason plants appear green). That being said we can get algae growth when we add these red lights, but the red nms are major contributors to healthy coral as well.
Secondly we are trying to replicate the sun which includes all the spectrums so we are get into the wishy-washy area where we are trying to improve mother nature here by focusing on only certain light spectrums that are being utilized while limiting those that naturally occur that are not (have to say this has been done with success with many T5s and MH that have higher spikes in the blue spectrum and still have great growth). I do wonder though if light in other spectrums is being used in small amounts much like trace vitamins are used in the human. If so we would see good growth for quite some time and then a slow taper to unhealthy coral as those molecules being produced are slowly depleted unless they are getting at least some light from another source.
My plan pending more reading so far will be:
Majority blue: ~50-60% (this will be a mix of blues)
White:~40%
Red: 4-5%
Other spectrums: 0-2%
These will be placed on separate drivers (considering using Rapid LEDs moon light driver for the other spectrums and the reds)
Lastly adding those other lights might actually create a more visually appealing tank being as we perceive all spectrums in the blue to red.

 

[NatureNerd]

If you look at the spectral output of Cree cool white, neutral white, and warm white LED's, you will see a fairly large amount of the power output is in the red part of the spectrum. They all cover the 630nm peak. I see no reason to add red when I look at these charts. Corals, or their symbiotic alga, may need some other peaks but, unless you can find a molecule that uses other parts of the spectrum it is hard to see how. It is also hard to see how marine biologists would have "missed" some photosynthetic molecule.

Below are spectral plots from the "white" LED's used in AI Sols and other commercial LED lighting. These are Cree XP-G Cool white, see the blue curve. The 630nm output power is 20% relative to the peak in the blue. That is quite a bit of the red.

I will say, for appearance only, I would like a little more of the red through yellow part of the spectrum in my lighting. I don't think the coral needs it, it just might be more pleasing for me to look at.

 

[NatureNerd]

Another set of questions to the experts... I once read that some coral pigments are used to protect the coral from too much light. Is this real? Is it wavelength dependent? Could this be an issue with LED's? (Assuming there is an issue at all)

 

[shrimphead]

problem with those cree's it a big part of that hump is unusable and also limmit's how intense you can put the light because of that unusable wavelength is unnatural to the coral and can be damaging to it if too intence but usable wavelengths can be cranked up above natural sunlight levels (found under water) because it can be used up and also reflected somewhat. although unusable wavelengths are reflected by the corals pigments as protection but can only handle so much of it.

 

[Steved13]

Some things to consider:

First: There is no red spectrum below ~14 feet of water, and obviously it reduces very quickly to that point. Red is filtered out very quickly. IMO if through millions of years of evolution, most livestock have learned to thrive without it, at this point they may be better off.

Second: white light contains all spectrum. White light contains Red.

Third: If you see any red in the tank, there is red light present.

Things (including coral and fish) aren't actually any certain color...they merely reflect that color from the light. If there is no red light to reflect, there would be no red to see. So the "white and blue LEDs" must have some red in their spectrums.

 

[shrimphead]

here's an interesting video i found on youtube about aquarium lighting. tells you about zooanthellea and their needs, coral pigments and discussions on different aquarium lighting including efficiency.
http://www.youtube.com/watch?v=g3vdfkqOLtU

 

[shrimphead]

double post

 

[cbellm]

Shrimphead has a good point in the light being absorbed at depths. I am not sure how deep it is before each is removed though. When I get off work I will have to read a it about it. It might be interesting to see growth rates at each depth as well. As reef keepers we obsess about fast grown (or at least maximizing it)

 

[NatureNerd]

here's an interesting video i found on youtube about aquarium lighting. tells you about zooanthellea and their needs, coral pigments and discussions on different aquarium lighting including efficiency.
http://www.youtube.com/watch?v=g3vdfkqOLtU

Good link but what the instructor doesn't seem to understand is the difference between relative output power graphs shown by vendors and absolute power graphs that should be used for these discussions. For the LED's, he keeps complaining about the large hump in the curve in the green through red part of the spectrum. What he doesn't understand is the Cree white curves could be drawn very close to his ideal sunlight curve with just a valley at the 480nm and a somewhat too large blue peak. Not that bad when compared to the same plot he showed for radium. He liked this plot. I could redraw those two plots with the same data and make the exact opposite case he made. The Cree plot would more closely match the natural sunlight plot.

He needed to scale up the sunlight case so that it could be clearly seen on his graph and use real units of power or energy and then plot the LED output curves with the broad hump at the same level. Obviously, it can be set there by adding LED's or increasing drive current. If he did this, the curves would look pretty close except for the valley at 480nm and a complete lack of any energy below 400nm. He obviously is very intelligent and knowledgeable about corals but he is not an engineer. If he showed the data this way, his argument about large spectral spikes damaging the corals would hold equally for the LED, MH, and T5 cases.

He also doesn't seem to get that with the sum of the Blue, Royal Blue and White, you could get pretty close to the ideal sunlight case, at least qualitatively by looking at the curves. By filling in lacking parts of the spectrum you can make a fairly smooth curve that looks a lot like the natural sunlight curve at 5 meters.

Also surprising was that he seemed to imply that the nice smooth curve was what was missing. But corals utilize light in fairly narrow wavelength ranges, if I understand it correctly. That means there is a large amount of unusable light in natural sunlight too, not just in our three primary artificial light sources (T5, LED, MH).

Thank you for posting the link. It was a good course. I would have loved to talk to the instructor as I am sure he could help clarify some concepts for me. One final takeaway is the point he made that when you take a coral from one environment (or lighting technology) and move it to another, the coral will probably suffer as it is not used to the overpowering of some pigments due to different spikes in the lighting. This might be why so many folks have problems when switching to LED's.

 

[NatureNerd]

At the closing of the class the instructor implied that for the "best" color of our corals, you need to match sunlight. Have you ever seen a sunlight lit tank? By today's standards, most folks would complain that the blues, purples, and greens looked boring and not saturated in such a tank. They would appreciate the yellow and orange corals but that is about it. We want healthy corals but we also seem to like that "pop" and deeply saturated color.

 

[shrimphead]

thought i would post this graph to show the chlorophyll absorbtion rates at different wavelengths. as you can see not much needed in the green yellow area. blue is mostly used.

 

[NatureNerd]

This may be a more complete picture...

 

[shrimphead]

whats violaxanthin and why is it significant ?

 

[Stuginski]

Hi reefers...how are you?
I don´t know if I´m wrong but...to my knowledge:

There is no other reason to use reds and greens other than aesthetics.

Green is out of the PUR peaks so photosynthesis couldn´t happen

Red is inside the second peak...BUT the photosynthesis don´t occur in zooxanthela as in plants. Some reactions to red light cause a uncopling of some steps of the photosynthesis chain, stoping the photosynthesis (red light teory).

Green = 0 photosynthesis
To much red = Bleaching!:mad2:

Dana Ridle talk about this points in a article in advanced aquarist magazine.:reading:

Hails from Brazil

D.