Minimalistic multichip DIY LED build
- Thread starter maglofster
- Start date
ac-rc said those drivers are dimmed by current and not voltage so if you want to control them with a reef keeper you will need to create a circuit that will take 0-10v and turn that into a variable current 0 being the highest resistance the pot has and 10v being the least resistance the pot has. im going to be making such circuit myself im not exactly sure how to yet but with a lil help from my guru cousin im sure we can come up with something
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mr.wilson
.Registered Member
I keep reading posts stating that blue light is all that corals need and white light is just for our enjoyment of the tank. Corals absorb light throughout the entire spectrum, and the most colourful tanks out there have lots of white light.
The corals we have in our aquariums come from 6-8' below the surface where even red light can penetrate readily. The CRI of blue light is very low so many pigments cannot be seen by the human eye. Fish colours are muted, white substrate appears blue, and coraline algae is invisible with blue light.
Low kelvin white light has too much green spectrum and subsequently causes corals to turn brown and nuisance algae to proliferate. There is a reason why the hobby abandoned 5,000k - 6,500k lighting many years ago. Low kelvin white LEDs do not necessarily have any more red light than high kelvin LEDs. They simply have less blue spectrum, replaced by green light for human vision.
First and second generation aquarium LED fixtures with just low kelvin whites and lots of royal blue light are notorious for giving corals dull colours and a lack of purples, blues, and red pigments.
The corals we have in our aquariums come from 6-8' below the surface where even red light can penetrate readily. The CRI of blue light is very low so many pigments cannot be seen by the human eye. Fish colours are muted, white substrate appears blue, and coraline algae is invisible with blue light.
Low kelvin white light has too much green spectrum and subsequently causes corals to turn brown and nuisance algae to proliferate. There is a reason why the hobby abandoned 5,000k - 6,500k lighting many years ago. Low kelvin white LEDs do not necessarily have any more red light than high kelvin LEDs. They simply have less blue spectrum, replaced by green light for human vision.
First and second generation aquarium LED fixtures with just low kelvin whites and lots of royal blue light are notorious for giving corals dull colours and a lack of purples, blues, and red pigments.
Mr Wilson, little off topic, but 6500k used to be the light recommended to grow Chaeto in our Fuges (Low kelvin white light has too much green spectrum and subsequently causes corals to turn brown and nuisance algae to proliferate. There is a reason why the hobby abandoned 5,000k - 6,500k lighting many years ago)) Do recommend 6500k lighting for this? Thanks---RICK
Lassef
Member
Adsorb and reflect is not the same. In reality they are completely opposed to each other. A wavelength absorbed, you will not see a color. It is simply gone, adsorbed in the tissue. A wavelength is reflected, you will see a color, it bounces back and does not adsorb. There are exceptions when certain wavelengths are partially absorbed and the rest of the energy is sent back as a photon with generally longer wavelengths. The name is fluorescence
For growth, it's certain areas where photosynthesis is active - the most important areas are 420-460 (470 nm from some sources), and the red areas around 630 and 660 nm
I would say mostly 8 - 12 ft. The penetration capacity of red wavelengths is not only depended of the deep - it is also depended of the turbidity of the water. The water over a coral reef has often a high turbidity caused by air bubbles mixed in to the water by the waves and breakers (land-wash) I have seen measurements and calculations (I think it was from the US Navy) that says the the red vawelenghts is totally gone already at 10 ft over a coral reef. IMO - for most corals the blue wavelengths is much more important for coral photosynthesis compared with the red wavelengths. The red you need - you will get it from the white LED:s. There is now also a reddish phosphorus coming up for the white LED:s
Totally agree
Sincerely Lasse
mr.wilson
.Registered Member
Green and red light causes algae to grow long at a fast rate. Blue light causes alage to grow slower but in a tight ball. From my experience 10,000K lighting is the best compromise for a refugium light.
I have been growing 200 mangrove trees under (2) 290w plasma lights for the past two years. I am planning to switch the two fixtures to 185w multichips in the next month. I will let you know if the growth rate or compactness of the trees changes.
One thing I have noticed is that refugium lights often grow cyanobacteria, while the display is completely free of it. This is either due to lack of flow or the higher content of red and green light. I have been able to rid a refugium of cyanobacteria by simply changing the LED from 7,500k to 16,000k. The growth rate with 16,000k was better, but it is a much brighter fixture (120w with tight optics vs. 85w with wide optics). I was able to repeat these results several times consistently.
Lassef
Member
See this:
Phycoerythrins ... 490nm, 546nm, 576nm ... in red algae and some
cyanobacteria
Phycocyanins ..... 618nm ................. in some red algae and cyanobacteria
Allophycocyanins . 650nm ................. cyanobacteria and red algae
Here you need red wavelenghts - see this
Chlorophylls:
Chlorophyll a .... 420nm and 660nm .... in all higher plants and algae
Chlorophyll b .... 435nm and 643nm .... in all higher plants and green algae
Chlorophyll c .... 445nm and 625nm .... in diatoms and brown algae
Chlorophyll d .... 450nm and 690nm .... in red algae
Carotenoids:
beta-carotene .... 425nm, 450nm, 480nm ... in higher plants and most algae
alpha-carotene ... 420nm, 440nm, 480nm ... in most plants and some algae
Luteol ........... 425nm, 445nm, 475nm ... in green and red algae and higher plants
Violaxanthol ..... 425nm, 450nm, 475nm ... in diatoms and brown algae
The zoox is often of diatom orgin - therefore probably chlorophyll C and Violaxanthol is the most important "Chlorophylls" to have in mind when you construct your light pattern for growth.
Sincerely Lasse
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mr.wilson
.Registered Member
14k white, 480nm blue, 450-465 royal blue, 410-430nm UV, 660nm red
To be fair, I have not used some of the other blues that Lasse is using (435, 445?) There is also a big difference between manufacturers phosphor mix. The big companies like Cree don't make chips redder, just more green (less blue). It is only the smaller Chinese companies that are adding phosphor coatings so there is no reliable standard. One manufacturer's 16k is another 12k, and one may have a lot of red, while another has more violet. As a matter of fact, many white chips that look "red" are actually violet, which is at the opposite end of the spectrum. That extra violet gives the chip a higher colour temp, yet the look of low colour temp.
The 14k white chips I use look more like Ushio 14k (whiter) than Phoenix 14k (bluer). There are also too many other factors in growth rates for me to firmly say I know the right answer. I do have some acros that have grown over 24" wide in a year under LEDs though.
Keep in mind that there is "show" and "grow" and you will not get the two at the same time, but you can have them in the same chip. In the old days, many people would use Iwasaki 6,500k bulbs which were white looking but still had a lot of blue on the spectrograph. These "white" lights were used during the day for growth, and were turned off at night and replaced by 10-14k MH so the viewer could enjoy more colour when they came home from work. Lasse's five channel multichip could carry out this same process. You have to decide whether you want to grow corals quickly or have a nice colourful tank, as the two don't always coincide.
Sanjay Joshi made a presentation at MACNA and was very clear that the blue light trend is absolutely NOT based in science and was contradictory to his personal observations as well. He showed a spectrograph that represented what light was best for coral. Dana Riddle has also clearly stated that while there are clear benefits to blue light, it is only one part or the necessary spectrum.
Keep in mind, you need to balance quality with quantity. Creating the ideal spectrum can lower the quantity of light required, but the cost difference between a 100w and 50w fixture is not that much. I would go with a broad spectrum that looks good to your personal taste and make sure you have more power than you need so you can dim each channel down to where you like & need it. Multichannel multichips do just that. Sure, you can run a 50w chip at 150, but there is a greater margin of safety if you run a 100w chip at 150w.
You can also play around with optics and suspension height. If you want to same money and clutter, hang the light higher and use 90˚ optics. You may only need 3 fixtures instead of 4 etc.
mr.wilson
.Registered Member
According to Dr. Sanjay Joshi, corals do not use Chlorophyll B; however, I do believe that the blue light article in Coral magazine stated that corals can adapt to different pigments under different lighting conditions (including ChlB)
read the whole thing, thanks alot to everyone participating!
now im starting to build one myown, already have everything lying around, cant wait for the weekend. will do 1x50w and 6x10w for testing purposes.
i also hope to see "dreamchips" available for every DIYer in the reefing community soon, thanks for your effort!
greetings, martin
now im starting to build one myown, already have everything lying around, cant wait for the weekend. will do 1x50w and 6x10w for testing purposes.
i also hope to see "dreamchips" available for every DIYer in the reefing community soon, thanks for your effort!
greetings, martin
TropTrea
New member
color balance is something that can be very misleading especialy to some newbee reading some of the above posts.
Fisrt off the Kelvine rating of a light source is not the ratio of blue to green light. One of the most important determinating factors is the ratio of blue to red light. However all three band widths are important. In many cases what are sold and advertised as 20,000K lights are realy no place near a true 20,000K rating since there color balance does not accuratly fit on any true K scale.
K rating is the equivelent color that a black body Iron glows at a specific temperature under the Kelvine scale. This glow is then ploted on a three dimensional color chart with the red, green and blue wave lenghts compared. A line is then drawn from true white to any said Kelvin balance and points nearest that color temp point determine the color temp a light source is recoggnized at. At 5,000K light source is the closest to perfect balance between all three band of light.
Red light does not just miraculious vanish at 5 feet of water or any specific level of the ocean. Yes the deeper you go the less there is of red light but it never goes away instead it just gets more difficult to measure because there is less there. Now stating at 5 feet or 10 feet it is gone is realy off because it is still going very strong and is usualy compared to meters not feet.
Look at the attenuation power of salt water more of a ratio. If your look at blue light for X meters of water it penetrates you might get only 90% of what was at the surface. But with green light it might be only 80% and red light only 70%. But when you penetrate 10 times deeper you do not automaticly loose all the red and green light instead you would get roughly 12 times more blue light as you get red light.
This same thing happens with UV light in the fact that the deeper one goes the more the UV is filtered out. However the actual filtering of the true UV light is much more than it is for even red red light. If you look at a light spectrums at various ocean levels you will see that the deeper you go the more the power spectrum peak moves from longer wavelenghts to the 430 nm range.
Green lighting does not cause algea bloom anywhere close to as much as red light does. As an example I have seen two completly different sources that indicate the cyno-algea thrive on light in the 680nm range. I have also found considerable reference to corals that do bleach out from light it the 660 to 680 nm range. But there are other shallow water corals that have been proven to florish under light in the 620 nm range. All these wave lenghts fall in the red band.
The floresent absorbantion band of light is strongest in the 430 to 460 nm range. However it does extend to as low as 400 nm and up as high at 520 nm. Besides this some coral pigments have been proven to absorb light in frequencies as long as 650 nm and as short as 380 nm. When your looking that 500 nm light it is in the green range much more so than the blue range.
While it is true that if your setting up a tank to grow just deep water corals the Royal Blue LED's are probably all you need for growth. However most of our corals are not exclusively deep water corals. Also if you looked at the ocean in deep water you would find it is dark and blue with only some florescense peaking back at you in other than the blue monoichromatic seascape. Most photography under water is using strong complementary lighting to fill in the lack that that is minimal to give you the beautiful pictures your looking at.
So in reality you are balancing out a dominant Blue tank as found in the deep ocean against the addition of other colors with full spectrum lighting to detect the reflected colors in the corals and rock for a blanced look to your eye. But please keep in mind everyones eye and personal taste is different.
Fisrt off the Kelvine rating of a light source is not the ratio of blue to green light. One of the most important determinating factors is the ratio of blue to red light. However all three band widths are important. In many cases what are sold and advertised as 20,000K lights are realy no place near a true 20,000K rating since there color balance does not accuratly fit on any true K scale.
K rating is the equivelent color that a black body Iron glows at a specific temperature under the Kelvine scale. This glow is then ploted on a three dimensional color chart with the red, green and blue wave lenghts compared. A line is then drawn from true white to any said Kelvin balance and points nearest that color temp point determine the color temp a light source is recoggnized at. At 5,000K light source is the closest to perfect balance between all three band of light.
Red light does not just miraculious vanish at 5 feet of water or any specific level of the ocean. Yes the deeper you go the less there is of red light but it never goes away instead it just gets more difficult to measure because there is less there. Now stating at 5 feet or 10 feet it is gone is realy off because it is still going very strong and is usualy compared to meters not feet.
Look at the attenuation power of salt water more of a ratio. If your look at blue light for X meters of water it penetrates you might get only 90% of what was at the surface. But with green light it might be only 80% and red light only 70%. But when you penetrate 10 times deeper you do not automaticly loose all the red and green light instead you would get roughly 12 times more blue light as you get red light.
This same thing happens with UV light in the fact that the deeper one goes the more the UV is filtered out. However the actual filtering of the true UV light is much more than it is for even red red light. If you look at a light spectrums at various ocean levels you will see that the deeper you go the more the power spectrum peak moves from longer wavelenghts to the 430 nm range.
Green lighting does not cause algea bloom anywhere close to as much as red light does. As an example I have seen two completly different sources that indicate the cyno-algea thrive on light in the 680nm range. I have also found considerable reference to corals that do bleach out from light it the 660 to 680 nm range. But there are other shallow water corals that have been proven to florish under light in the 620 nm range. All these wave lenghts fall in the red band.
The floresent absorbantion band of light is strongest in the 430 to 460 nm range. However it does extend to as low as 400 nm and up as high at 520 nm. Besides this some coral pigments have been proven to absorb light in frequencies as long as 650 nm and as short as 380 nm. When your looking that 500 nm light it is in the green range much more so than the blue range.
While it is true that if your setting up a tank to grow just deep water corals the Royal Blue LED's are probably all you need for growth. However most of our corals are not exclusively deep water corals. Also if you looked at the ocean in deep water you would find it is dark and blue with only some florescense peaking back at you in other than the blue monoichromatic seascape. Most photography under water is using strong complementary lighting to fill in the lack that that is minimal to give you the beautiful pictures your looking at.
So in reality you are balancing out a dominant Blue tank as found in the deep ocean against the addition of other colors with full spectrum lighting to detect the reflected colors in the corals and rock for a blanced look to your eye. But please keep in mind everyones eye and personal taste is different.
mr.wilson
.Registered Member
Photosynthetically Active Radiation (PAR), as measured by a quantum meter, includes any light between 400-700nm.
If you were to illuminate a coral tank with exclusively 420nm - 460nm light you would have very little colour or growth in your corals. In order to find light that is purely below 465nm, one would have to go 500m deep, where there are no photosynthetic corals and only bioluminescent fish.
If you look at the spectrograph of a MH or T5 lamp, you will see a spike in the red. You will not see this in any white LED chip on the market regardless of phosphor mix.
Most of the corals we buy are maricultured. They grow in crystal clear waters that are 6' deep at low tide and 8' deep at high tide. The farmers walk out at low tide to collect the corals. Even wild harvested corals are from clear water that is shallow. They do not use any scuba gear and do not free dive to great depths when there are many corals near the surface.
Blue photons have more energy than red photons, so corals need to do something with that excess energy. This may be redirected as fluorescence or it could generate heat in the coral tissue. This study shows that Galaxea coral grows better under white light (plasma) than blue light (LED), but there was no conclusion if the extra heat caused by the blue light was a mitigating factor. In the article, they state that greater flow could have dissipated the extra heat, but this is certainly something we do not take into consideration when lighting our reef tanks.
http://www.advancedaquarist.com/blo...d-to-be-highly-suitable-for-coral-aquaculture
Blue light is very effective in reef tanks, but that doesn't mean that we need to add more than is necessary. The Blue light article in Coral magazine showed the value of blue light, but it did not state that we need to use more of it.
mr.wilson
.Registered Member
Sanjay and Dana have not published their most recent articles yet. Here are some reflectance graphs that Sanjay posted somewhere else.
mr.wilson
.Registered Member
What I was trying to say with regard to low kelvin LEDs is that people have a misconception that a 7,500k LED has more red light than a higher colour temp LED. The 7,500k light simply has less blue light, so the colour temperature is lower. Phosphors can be added to a blue light to add red, thus making an LED that has more blue and more red than a typical 7,500k LED reading light with lots of 555nm green light. In other words, adding a row of 7,500k LEDs doesn't guarantee that you are broadening the spectrum anywhere other than green light.
There is evidence that red light causes coral bleaching, but LED fixtures with 10% red light still have less red light than many T5 & MH lights, so there is no danger of bleaching.
Lassef
Member
With all respect - you show graphs of the reflectance. For me this shows how the different photons (wavelengths) reflects - and indirectly how they absorbs. The lower the reflectance is - the higher the absorbency is
The graph reflectance spectra - 2 clearly shown that photons in the area of 410 -460 are reflected less. With other words this wavelengths is adsorbed most. Adsorbed = the energy from this photons are used in one or another process. You can also clearly see a dip at around 660 - 680 nm in reflectance - it means that these photons are absorbed and the energy is used. Is nearly the same with the second graph - its only that it starts at 350 nm. All of these graphs indicate for me that the important biological use of different wavelengths (photons) happens in the area of 400 - 460 nm. And in some degree around 660 - 680 nm.
The only thing you say here is that the intensity of the blue light at wavelengths of 420 - 460 nm at 500 m deep is not enough for photosynthesis. The deeper it is - lesser intensity. Compare with that I take 4 pcs of 1 watts LED (420,430, 445 and 455) and try to have corals living in a 60 cm deep tank
You forget to mentioned that the author mentioned excess oxygen as a possible cause to less growth -and they said (bold from me)
Why is the oxygen accumulation important? Thats because it is a waste from the photosynthesis. Many, many plants and algae can at high photosynthetic levels produce so much oxygen ( and resulting active oxygen radicals) that it damage the tissues. Many corals has been shown to form anti radical compound - just in order to deal with this problems.
I have warned before just for the power of photosynthesis that you probably have in the wavelengths of (420 - 460 nm). If someone is introduce this wavelengths with power LED - take it carefully - rise the intensity during at least a month.
Everyone that have deal with corals know the important of water current in the tank when you have intense light. This is partly just because that during intense photosynthesis - the corals produce a lot of oxygen and they need to get rid of this - the process to transport it out from the tissue is driven by difference in concentrations so they need rather low oxygen levels just close to the tissue. A strong water current will all the time take away excess oxygen in the micro habitat around the tissue of the corals.
Sincerely Lasse
mr.wilson
.Registered Member
Every coral has its own unique lighting requirement, even within a common group (LPS, SPS, soft coral). The way I read those charts, blue and red light is absorbed more readily, but light is absorbed throughout the spectrum. Even the wavelengths with the greatest reflectance rate, still absorbed 40% of the light. Just because these wavelengths are absorbed to a lesser extent, doesn't make them any less important.
The average Swede absorbs a high proportion of meatballs, but it doesn't make lingonberry sauce any less vital to our survival as an ethnic group
We had a discussion about red light earlier on in the thread where I was challenged on the value of 680nm light, now I'm seeing its value used to argue the benefits of pure blue light somehow?
One has to work under the assumption that nature knows better than us, and corals have adapted over millions of years (5,000 years for our creationist members) to full spectrum light and have not flourished in the depths where only blue light penetrates. Coral populations will tend to settle out where the conditions are best, and lighting is one of the key factors. If there are more nutrients available at a different depth they will simply adapt to the lighting which will now become "ideal".
I think hobbyists read too much into absorption and reflectance charts, and miss the obvious. The blue light article in Coral magazine showed the benefits of blue light, but did not indicate that reef lighting needs to be any more blue than standard T5, MH or LED selections, which are all quite blue.
My point is that many people have the misconception that the corals they keep in their aquariums come from blue water and they are replicating the natural habitat by using heavy blue light. I am happy to concede that personal aesthetics lead people to desire a blue tank. I just don't want people to fool themselves that they are doing it for the benefit of their corals.
The other aspect is that people may think that they can offer a spectrum that is better than that found in nature. We can provide perfect storm and cloud-free days and manipulate the photoperiod. We can also pick a spectrum that discourages the brown colour of symbiotic algae by avoiding the spectrum that is absorbed by zooxanthellae. We can even pick a spectrum that fosters vivid photo pigments, but we cannot improve upon the health and growth rates of natural sunlight.
If you want to focus on photosynthetic energy, than a 6,500K Iwasaki MH bulb is perfect. The corals will be brown, but they will grow like crazy. Most hobbyists are looking for enough symbiotic algae to reach the compensation point early in the day so the coral can gain energy with few resources expended. After that, the focus is on reflecting and generating vivid pigments. A narrow band of blue light simply will not achieve these goals.
