DIY LED Array build
- Thread starter sphil876p
- Start date
der_wille_zur_macht
Team RC
Haven't put photos up yet. They're still on a camera, packed away somewhere (I moved a month or two ago and haven't really settled in yet!)
james3370
Premium Member
it will be some time before i am in a position to setup another tank, but unless things change between now & then, i'll probably go w/ a 1:1 ratio of blue:white independently dimmable for color matching as described earlier & maybe a 10:1 of red/uv:blue/whiite to get a lil red & uv spectrums in there as well. since it won't be a huge tank, i can probably get them on 1 or 2 buckpucks & dim them accordingly as well
i moved a month ago & still have a dining room full of boxes LOL
need to go thru it all & probably trash a good bit of it before it all goes in storage when i leave for basic training :uzi:
der_wille_zur_macht
Team RC
Consider the difference in upfront cost vs. longeterm cost. An LED array will likely win out after a few years, given the cost to replace lamps and the higher electricity consumption for T5, PC, MH, etc.
james3370
Premium Member
if i'm not mistaken, the "bin" is a clasification on the LED's measured spectrum & efficiency.....like the 4 Cs of a diamond LOL....the higher the bin, the higher the quality of the LED
Santoki
Shimmer Addict
with all this talk about spectrum, does anyone have any data plots for sunlight spectrums that actually make it past 5 meters under water? I would think it makes sense that chlorophyll adapted for land or extremely shallow waters might be using the red spectrum, ie the algae on your turf scrubber, but most corals we keep I think have little use for the red spectrums. When diving, or taking pictures of the reef under water without flash, reds hardly show up at all, supporting my observation that not much red light gets down there...they appear almost black or brown.
der_wille_zur_macht
Team RC
Pretty much.
The manufacturers don't have infinite control over parts this extreme, so they basically make them "close" to a certain target spec, then test a few units from each batch - or, purposefully tweak the target on different runs, so the product covers a wider range of specifications.
Then, the product is broken up in to "bins" based on certain parameters.
For these high power LEDs, the two main criteria are color and brightness (which translates pretty cleanly to efficiency). Most people talk about the brightness bin, and ignore the color bin, though it comes up from time to time.
For example, the Cree XR-E is available in 12 brightness bins. The worst, M2, is only 40 - 45 lumens at 350mA. The best, Q5, is 100 - 107 lumens @ 350mA. Cree brightness bins are a letter followed by a number, and are sequential. So, a Q5 is one "step" better than a Q4, which translates into about 7% improvement.
One of the main reasons given for building an LED array is increased efficiency (in terms of electricity consumed and heat generated per unit of light produced) compared to MH or fluorescent lighting. When you look at the above numbers, it should be clear that knowing the bin you are buying is critical. If you just know you're getting an XR-E and aren't sure which bin it's in, you might end up with 40 lumens per watt of electricity, or 100 lumens per watt!
jonnybravo22
New member
Phil I didn't get clarity on how you're preventing salt creep with the spotlight.
What kind of cover are you using? Can you post a pic?
What kind of cover are you using? Can you post a pic?
I use acrylic shields...
This one I cut to a rough shape then ground it to fit inside the fixture on my bench grinder..
jonnybravo22
New member
oh.... then i guess i had too much clarity - I cant even see it! i thought that screw was holding your heatsink.
how are each of those being held into place (heatsink and acrylic sheild) -- is the acrlyic deep enough that you were able to put a screw through it?
how are each of those being held into place (heatsink and acrylic sheild) -- is the acrlyic deep enough that you were able to put a screw through it?
The 1/4" acrylic holds everything in the fixture. I just drilled a few holes around the outside of the fixture, and ran the screws into the edge of the acrylic disk.
greenbean36191
Premium Member
DWZM asked me last week if I could help shed some light (pun intended) on the color-loss issue with the corals. I'm a little late to the game since I haven't had the time the past week to write out the long response this question requires. Hopefully I'm not too tired to keep this post coherent tonight.
First of all, I'll tell you right off the bat that this information is really more for your consideration rather than making good recommendations about what you should do with the lighting setup. Even with good data, there are way too many unknowns on the subject of coloration in corals to make specific suggestions. Without more data it's kind of like taking a car to the mechanic and telling him it's just not running right and expecting him to fix it.
What I told DWZM earlier is that when you're trying to design the best lighting, you need to consider the effects of the light on the animal and the effects of the light on the zooxanthellae since they behave very differently. They've been sort of lumped together here which makes an already confusing subject even more so. You also might want to think about the efficiency of your lighting vs. the output spectrum.
First, consider the animal. The bright colors that most hobbyists want from their corals are produced by the animal and have nothing to do with the zoox other than that they can reflect light towards them or they can shield the zoox from the light. They modify the spectrum and intensity of the light hitting the zoox. The regulation of these pigments is poorly understood, but their production and location in relation to the zooxanthellae (above or below them) is thought to be dependent on lighting intensity. The actual spectrum of the light is of secondary importance. A common misunderstanding here is that they are induced by UV light, which doesn't seem to be the case. UV induces production of mycosporine-like amino acids, which are the sunscreen for the coral. They don't contribute to the color though.
Dana Riddle has an excellent series on the effects of different lighting on the production of coral pigments.
http://www.advancedaquarist.com/2009/1/aafeature1/view?searchterm=
http://www.advancedaquarist.com/2009/2/aafeature1/view?searchterm=
http://www.advancedaquarist.com/2009/4/aafeature1/view?searchterm=
Second, consider the effects of the light on the zoox. Again, intensity is thought to be more important than spectrum in most cases. One of the most common ways to measure intensity, and probably the most familiar to hobbyists, is PAR. It's nothing more than an unweighted count of photons hitting a surface per unit of time. Except at low intensities or under spectra very skewed towards a particular color, this tends to be a good metric for photosynthesis.
But hold on. Where does the activity spectrum come into play in all of this? The activity spectrum tells you two things. The first thing it tells you is what percentage of photons of each color are absorbed by the zooxanthellae. The second thing it tells you is the relative intensities required to reach saturation for each color. Also, it's important to keep in mind that the activity spectrum is for the zooxanthellae in isolated culture, not as it occurs in the coral. Even if you had a light tuned exactly to match the activity spectrum of the zooxanthellae, it would be modified by the coral before it even got to the zoox, so trying to to approximate the activity spectrum isn't necessarily the goal to shoot for. What the activity spectrum does NOT tell you is how useful a photon is for photosynthesis once it is absorbed. All photons within the PAR spectrum are equal in their ability to produce sugar after they are absorbed. A blue photon has more energy than a red photon, but only the energy equivalent of a red photon actually gets converted to sugar. The rest gets lost as heat or fluorescence (but you won't see it without special equipment).
So what does that mean? It means that they're very good at catching blue photons, but most of that energy doesn't go towards food. On the other hand, they're only ok at catching red photons, but most of that energy gets converted to food. The difference between the two cases is usually not very important except when the intensity is well below saturation, so there are few photons available. Otherwise you're talking about something like 40% chance of catching each of 10^20 photons, which is still a pretty good chance of catching a lot.
Since the difference doesn't matter much at higher intensities, we can use simple measurements like PAR to get a decent idea of photosynthetic rates. The more PAR, the more photons hitting the surface, and the more photosynthetic reactions taking place... up to a point. That point is saturation. All saturation is is a point where so many photons are being absorbed that the electrons they excite cannot be shuttled through the chain reactions any faster, regardless of how many more photons you bombard the zoox with. If intensity continues to increase, the zoox start shunting some of the electrons into other pathways (actually this is occurring earlier too, just not as much). The transfer of electrons down the chain is a bit sloppy too, so some leak out and form reactive species. As intensity increases you start to get into sort of an I Love Lucy situation where the sloppiness increases and you get more and more reactive species being formed and more damage accumulating from their interaction with cellular structures. That causes the rate of photosynthesis to drop off (photoinhibition), and if it happens for a while, it leads to bleaching.
So in theory at least, bluer light gives better photosynthesis (though only marginally except cases well below saturation) and better coloration. Higher intensity does the same, up until it becomes too high and causes damage, in which case it can slow growth and give washed out color.
With lamps like MH and fluorescents that don't have much tunability as far as input wattage, the rule of thumb is that bluer bulbs have lower PAR due to basic physics. If you want to increase intensity without a lighting upgrade you have to change to a yellower bulb. However, LEDS should give you more options to change intensity independently of color, which is a bit of a game changer.
If this were my tank and I was having this problem, I would try to get a PAR reading to give some vague starting point. Is the intensity high or low? Unless it's very high, I'd probably just tune the light to be a little bluer if it's possible. If it is very high, I'd probably leave the color the same and turn it down. YMMV.
Yes, it is all very confusing, even for people like myself who are supposed to understand this stuff, but hopefully all of this helps just a little bit.
First of all, I'll tell you right off the bat that this information is really more for your consideration rather than making good recommendations about what you should do with the lighting setup. Even with good data, there are way too many unknowns on the subject of coloration in corals to make specific suggestions. Without more data it's kind of like taking a car to the mechanic and telling him it's just not running right and expecting him to fix it.
What I told DWZM earlier is that when you're trying to design the best lighting, you need to consider the effects of the light on the animal and the effects of the light on the zooxanthellae since they behave very differently. They've been sort of lumped together here which makes an already confusing subject even more so. You also might want to think about the efficiency of your lighting vs. the output spectrum.
First, consider the animal. The bright colors that most hobbyists want from their corals are produced by the animal and have nothing to do with the zoox other than that they can reflect light towards them or they can shield the zoox from the light. They modify the spectrum and intensity of the light hitting the zoox. The regulation of these pigments is poorly understood, but their production and location in relation to the zooxanthellae (above or below them) is thought to be dependent on lighting intensity. The actual spectrum of the light is of secondary importance. A common misunderstanding here is that they are induced by UV light, which doesn't seem to be the case. UV induces production of mycosporine-like amino acids, which are the sunscreen for the coral. They don't contribute to the color though.
Dana Riddle has an excellent series on the effects of different lighting on the production of coral pigments.
http://www.advancedaquarist.com/2009/1/aafeature1/view?searchterm=
http://www.advancedaquarist.com/2009/2/aafeature1/view?searchterm=
http://www.advancedaquarist.com/2009/4/aafeature1/view?searchterm=
Second, consider the effects of the light on the zoox. Again, intensity is thought to be more important than spectrum in most cases. One of the most common ways to measure intensity, and probably the most familiar to hobbyists, is PAR. It's nothing more than an unweighted count of photons hitting a surface per unit of time. Except at low intensities or under spectra very skewed towards a particular color, this tends to be a good metric for photosynthesis.
But hold on. Where does the activity spectrum come into play in all of this? The activity spectrum tells you two things. The first thing it tells you is what percentage of photons of each color are absorbed by the zooxanthellae. The second thing it tells you is the relative intensities required to reach saturation for each color. Also, it's important to keep in mind that the activity spectrum is for the zooxanthellae in isolated culture, not as it occurs in the coral. Even if you had a light tuned exactly to match the activity spectrum of the zooxanthellae, it would be modified by the coral before it even got to the zoox, so trying to to approximate the activity spectrum isn't necessarily the goal to shoot for. What the activity spectrum does NOT tell you is how useful a photon is for photosynthesis once it is absorbed. All photons within the PAR spectrum are equal in their ability to produce sugar after they are absorbed. A blue photon has more energy than a red photon, but only the energy equivalent of a red photon actually gets converted to sugar. The rest gets lost as heat or fluorescence (but you won't see it without special equipment).
So what does that mean? It means that they're very good at catching blue photons, but most of that energy doesn't go towards food. On the other hand, they're only ok at catching red photons, but most of that energy gets converted to food. The difference between the two cases is usually not very important except when the intensity is well below saturation, so there are few photons available. Otherwise you're talking about something like 40% chance of catching each of 10^20 photons, which is still a pretty good chance of catching a lot.
Since the difference doesn't matter much at higher intensities, we can use simple measurements like PAR to get a decent idea of photosynthetic rates. The more PAR, the more photons hitting the surface, and the more photosynthetic reactions taking place... up to a point. That point is saturation. All saturation is is a point where so many photons are being absorbed that the electrons they excite cannot be shuttled through the chain reactions any faster, regardless of how many more photons you bombard the zoox with. If intensity continues to increase, the zoox start shunting some of the electrons into other pathways (actually this is occurring earlier too, just not as much). The transfer of electrons down the chain is a bit sloppy too, so some leak out and form reactive species. As intensity increases you start to get into sort of an I Love Lucy situation where the sloppiness increases and you get more and more reactive species being formed and more damage accumulating from their interaction with cellular structures. That causes the rate of photosynthesis to drop off (photoinhibition), and if it happens for a while, it leads to bleaching.
So in theory at least, bluer light gives better photosynthesis (though only marginally except cases well below saturation) and better coloration. Higher intensity does the same, up until it becomes too high and causes damage, in which case it can slow growth and give washed out color.
With lamps like MH and fluorescents that don't have much tunability as far as input wattage, the rule of thumb is that bluer bulbs have lower PAR due to basic physics. If you want to increase intensity without a lighting upgrade you have to change to a yellower bulb. However, LEDS should give you more options to change intensity independently of color, which is a bit of a game changer.
If this were my tank and I was having this problem, I would try to get a PAR reading to give some vague starting point. Is the intensity high or low? Unless it's very high, I'd probably just tune the light to be a little bluer if it's possible. If it is very high, I'd probably leave the color the same and turn it down. YMMV.
Yes, it is all very confusing, even for people like myself who are supposed to understand this stuff, but hopefully all of this helps just a little bit.
babyjess210
Active member
Ok after reading 10 pages and getting a bad headache. QUESTION??? So if i buy a meanwell ELN-60-48D and run 12-13 LED on a single driver I can hook up a cheap $2 pot and dim that string of LED. In other word the driver will have 2 extra wires(i think it blue and white) and those 2 wires goes to the pot??
Thanks
Kenny
Thanks
Kenny
kcress
New member
Coherent enough! I learned quite a bit. Thanks for the education.
Not knowing much about coral yet I have a question:
Are you saying that photons strike the coral membranes and get absorbed and re-emitted to the internal algae possibly frequency shifted, or the photons just pass thru a membrane capable of filtering/controlling various spectra to the algae?
Hope your moves goes well.
greenbean36191
Premium Member
The pigment layers that give corals their colors can be used to modify the light hitting them. Depending on intensity and possibly on spectrum, the coral will shift the location of the layer relative to the zoox.
When the pigment is in front of the zoox it can act like a filter. Some photons are blocked from reaching the zoox altogether by being absorbed or reflecting by the pigments. Others are absorbed by the pigments and then re-emitting at longer, less energetic wavelengths (fluorescence), with some of the re-emitted photons striking the zoox. In the first case the intensity of the light hitting the zoox is altered, and in the second, the spectrum is altered.
Behind the zoox the pigments can act like a mirror, where they reflect photons, or again absorb and then re-emits them at different wavelengths. This helps in low light intensities where every photon counts. Those that slip past the zoox on the first go-round can be stopped by the pigments and reflected or re-emitted back towards the zoox for another shot at being absorbed and used for photosynthesis. In both cases the intensity AND spectrum of light hitting the zoox can be altered.
Which photons have which fate depends on the color and types of the pigments. In the case of non-fluorescent pigments, the color you see is just the color of the photons that are reflected. In the case of fluorescent proteins, they usually affect blue, violet, and sometimes UV or green photons (which is why we use actinic bulbs to bring out fluorescence). They use that photon's energy to excite an electron and then re-emit a photon at a longer wavelength. So you might have a violet photon re-emitted as a green one or a blue one re-emitted as red.
These pigments are a huge part of why it's so hard to make solid recommendations about lighting to solve specific coloration issues. The spectrum reaching the zoox can (and usually is) highly modified from the spectrum striking the surface of the coral.
When the pigment is in front of the zoox it can act like a filter. Some photons are blocked from reaching the zoox altogether by being absorbed or reflecting by the pigments. Others are absorbed by the pigments and then re-emitting at longer, less energetic wavelengths (fluorescence), with some of the re-emitted photons striking the zoox. In the first case the intensity of the light hitting the zoox is altered, and in the second, the spectrum is altered.
Behind the zoox the pigments can act like a mirror, where they reflect photons, or again absorb and then re-emits them at different wavelengths. This helps in low light intensities where every photon counts. Those that slip past the zoox on the first go-round can be stopped by the pigments and reflected or re-emitted back towards the zoox for another shot at being absorbed and used for photosynthesis. In both cases the intensity AND spectrum of light hitting the zoox can be altered.
Which photons have which fate depends on the color and types of the pigments. In the case of non-fluorescent pigments, the color you see is just the color of the photons that are reflected. In the case of fluorescent proteins, they usually affect blue, violet, and sometimes UV or green photons (which is why we use actinic bulbs to bring out fluorescence). They use that photon's energy to excite an electron and then re-emit a photon at a longer wavelength. So you might have a violet photon re-emitted as a green one or a blue one re-emitted as red.
These pigments are a huge part of why it's so hard to make solid recommendations about lighting to solve specific coloration issues. The spectrum reaching the zoox can (and usually is) highly modified from the spectrum striking the surface of the coral.
Reef_Matrix29
Water Lover
Thank you Greenbean36191! This makes perfect sense and the long and short of it seems to be (IMO): as we make these DIY LED fixtures and are striving for the most powerful LEDs and correct color ratios, dimming and etc., we need to be also aware of the intensity of the light emitted and whether "brightest" to our eyes is really a bad way to determine "healthy" for the corals. When I turned my lights down (2 x 36 LED arrays @ 1:1 white to blue) from 700mA to 350mA, the corals seemed to be not as stressed for the few days I had it there, but the tank looked so dim to my eyes. Can it be that while LEDs are efficient in their light output, that what we consider bright and intense may need to be re-thought when switching to such efficient light sources? Maybe we are over-thinking not only the cooling of the arrays, but also the intensity of our fixtures. Basically, more with less seems to be coming to my mind...
I need some help with the design of my array. I have a 48" long bow front that is 24" wide in the center and 29" deep. I keep Sps and have 3 clams on the sand bed. Will 108 LEDs be enough, how far apart should I space them if I plan going with 3 heat sinks two 15 long and one in the center 19 inches long? Will I need to use 60 degree optics to get light down to the sand bed?
Similar threads
