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Thread: LED Lighting and Robust Algae

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    LED Lighting and Robust Algae

    Note: I posted what you see below on another forum. It garnered little response. I suppose that can be understood as only a small percentage of that large audience is experimenting with ATF/S. So with approval from the moderators I am placing the topic here. I have edited out the few responses received and I will make adjustments as necessary for the purposes of clarity.

    What I have written so far is more a stream of consciousness than any one specific thing. I'm trying to grasp this material and am hoping those more knowledgeable can shed light on some of these areas. It won't take much to exceed my range of knowledge. But I think there's alot to be learned on the topic.

    ----------------------------------------

    I have looked at more spectrum graphs and read more forum posts and browsed more published articles in the last few week than...

    From what I have been able to cull from all this reading is that Chlorophyll A responds in the 430 and 660NM ranges and Chlorophyll B responds in the 455 and 640NM ranges. I have also noticed some references to carotenoids and their response in the 470 to 500 NM range.

    So here are some observations/questions:

    Much of what I have read on the various marine aquarium sites regarding LED's and turf scrubbers focused almost exclusively on the "deep red" range and the mention of light in the blue regions is thrown in as an "if you really want to". This addresses just the red end of chlorophyll A and pretty much ignores chlorophyll B. I can't say I've really run across any discussion regarding providing beneficial light spectrum for carotenoid development even though carotenoid seems quite beneficial to the overall health and vigor of these algae.

    So, in general, does it really matter? What I mean is, does practical application show that specific light spectrum isn't as crucial as much of the published information lead you to believe?

    My assumption is that the published articles on marine algae would be based upon some empirical evidence, i.e., someone tried growing algae with 630nm light and had poor results compared with 660nm. As I look at the spectral distributions on some of these diodes, the spread is about 15nm wide to -50% output point. Taking as an example the Cree XP-E- it has zero output in the 660nm range. Yet, the XP-E is marketed by well-regarded suppliers as an "algae scrubber diode".

    Then, looking at warm-white fluorescents, their output in the red range peaks in the low-600 range, but noticeably, they all seem to have a big bump in the green range, in the low 500's. That's where the carotenoids live.

    From all of this, I'm looking at some potential explanations...

    --These algae will grow with just one of the three photosynthetic compounds supplied proper light.

    --The above, but with only one of the two parts of the spectrum in their needs range (ex: Chlor. A, only 660nm/no 430nm.)

    --These algae will grow with light close to but not exactly in their ideal spectral need range.

    --Algae will grow if you shine a flashlight on it.


    I kept reef tanks 20+ years ago. I'm returning to the hobby now- I figure if I can keep two kids alive long enough to graduate college I can probably keep a captive reef. But, I learned back then that success with a marine aquarium isn't keeping it going for a year, it's keeping it going for a decade. My concern is constructing something that will work OK but unbeknownst to me, is nothing more than a delayed catastrophic failure.

    ---- Then----

    (In answer to a comment about a recent changeover from CFL to red/blue LED)
    If you're using royal blue and 630 red, your algae shouldn't grow all that well. And to your comment about CFL's, if you were using one of the readily-available 2700k bulbs, most likely it had a very broad spectral band, including a good amount of green. Compare that to a blue/red setup which has two 15nm wide peaks in a 350 nm wide band of light. The CFL is maybe something that can be chalked up to intensity... Or maybe all CFL's aren't created equally- in fact, I know this to be true.

    As I continue to read, I see a broad spectrum of successes and failures with ATS systems and most of the discussion is centered around water flow and food inputs. I'm beginning to wonder if the issue isn't two people with the identical setups having different results isn't because they don't really have identical setups. If you look at any of these color LED's, they're sold as, for example, royal blue advertised as 455nm. But out of a random batch, I could get a bin with as much as 25% light output and a spectral peak 25nm different than yours. So if the research I have read is to be believed, my new red LEDs might be putting out a light spectrum that's almost invisible to my algae and yours is in the exact needed spot. But we are both using the same LEDs.

    This leads me to wonder about the people using CFL's and their relative successes and failures. CFL spectral curves are much more broad than an assemblage of color-specific LEDs. But even then, not all two are the same. Different manufacturers get to 2700K in different ways. Just as LED manufacturers do. Some neutral white LEDs have strong output in the red spectrum and some don't at all. But they're sold at the same color temperature and relative CRI.

    I know LEDs hold the most promise for algae propagation. But is success or failure a matter of what got randomly grabbed out of a parts bin?

    ----Then----

    The more I read, the better I am able to grasp just how little I know.

    There seems to be a common assumption that chlorophyll is chlorophyll and it functions the same in each organism that it is contained in. That doesn't seem to be the case.

    I have seen a number of light curves identifying the photoreactive light frequencies that certain chlorophylls react at. But there's another element- it's referred to as the action spectrum of photosynthesis. These are much broader curves, not the 15nm wide spikes shown in the previous charts.

    A couple other elements are carotenoids and phytochrome. From what I am gathering, carotenoids provide some photosynthetic benefit plus also aid in protecting the algae from IR. Phytochromes are photoreactive in the far-red ranges. I'm just starting to attempt to understand their contributions. In short, the picture that I'm beginning to see is that you can grow algae in most light- I have read more than a few times how light-adaptive it is. But at the same time, provided optimal light, it grows much more strongly. Strong, health algae strips bad stuff out of the water more quickly and efficiently, and out-competes undesirable species on the growing substrate.

    Some other things that I have been reading about are the effects of far-red light. This is from 660nm out to 760nm. Some of the literature I have read speaks to far red adding significantly to algae's co2 fixing and potassium uptake abilities.

    Beyond that, I have come across some fairly new research coming from artificially-lighted agricultural applications where they have been supplementing far red into the end of the light cycle's photoperiod. The theory here being that this is one of the triggers that plants react to in order to compete for light. Exposure to this spectrum causes both enhanced growth and a stronger root system. This very much goes against the prevailing notion that it's just a plant and it's Ok to just flip the lights off. By the way, this is coming from a USDA funded initiative to investigate the application of LED's in artificially lit agriculture.

    I think another observation from all of this is that once the lights go out, the algae goes to sleep. CO2 fixation and potassium uptake drops to a small percentage of daylight processing quantities. This alone has me questioning having only one algae panel instead of two operating on opposite schedules.

    The rub is that the majority of legitimate scientific research is aimed at wastewater treatment, biofuel aqua-crops and towards the elimination of "problem algae". I have found nothing much beyond the marketing information generated by light manufacturers selling to the reefkeeping hobby. All of what i have seen there is very non-specific. Even in the legitimate research, there are broad variances in light requirements between closely related algae species. Some light a decent dose of green light. Some like blue down in the 430nm region.

    I think what we are confronted with is a particular limitation in available LEDs. 20-some years ago (or so) the solution we all believed to be ideal was metal halide lighting. Aside from their inherent shortcomings of power consumption, heat output and short lifespan, they do present a one-size-fits-all light spectrum. LED's just don't work the same way. If you look at the spectral distribution of any high-CRI diode, it looks nothing like the MH.

    If you look at the breakdowns of commercially available lights over on ledgroupbuy.com, it's apparent that the commercial manufacturers are using the throw the kitchen sink approach at the issue. If you have one of everything, it must be OK, right? In essence they're mimicking the MH spectrum. But some of this research shows that might not be the best approach, especially when you're talking about implementing far red.

    On this next one I am very far outside my range, but the dope-grower guys are using far-red supplement in various fashions to first inhibit and then trigger flowering. I have so little knowledge of botany, I have no idea if there's any sort of analog here. Does hair algae flower? I sure can't answer that.


    ----Then----

    I first found the USDA reference here-

    http://www.actahort.org/chronica/pdf/ch5201.pdf

    and from there googled until I got to here-

    http://leds.hrt.msu.edu/assets/Uploa...ation-2011.pdf

    which led me to here-

    http://leds.hrt.msu.edu/publications/

    which appears to be a treasure trove of LED research into horticultural applications, that I have yet to delve into. It's not easy when you have to look up the definition of every third word and once a paragraph you have to look up a basic biology concept that they didn't teach much about in engineering school.

    As far as the MH usage, I like to think of that as "the American Approach". If a little works, use more. If you only need a small segment of the overall, don't sweat it. Huge energy usage and heat byproduct we have to refrigerate away? To hell with it- just turn the knob to eleven. Wait, that sounds like the way I've done just about everything since childhood.

    With all due respect to the people in the aquarium biz who are selling LED solutions, what they are putting forth is a consumer product. They may love the hobby, but it's a business pursuit. Thus, what they're selling is a dot somewhere on a 3-D matrix of considerations of cost, manufacturability and product performance. What they're selling isn't, and doesn't have to be, perfect. It just has to work to some degree that enough people will purchase it in a quantity large enough to sustain their enterprise. It will improve as competition pressures each supplier to refine their product. I sincerely doubt that any one of them has done anything more than what I have begun to do. There's tons of research out there on light spectrum effect on photosynthesis, the origins of which are well over a hundred years old. Some of the best research was done in the 60's and 70's and just now is being expanded upon and researched in more depth. I would surmise there are two reasons for this. First, the art and science of LED's has recently progressed by an incredible amount. And in the last 4-5 years, energy costs have skyrocketed (thanks Barry!). I couldn't fathom that there's an aquarium grow light manufacturer out there that has done extensive (or any) action spectrum research with multiple algae and multiple spectral curve experiments. If there was, you would see this front and center in their marketing materials. Instead you see "Our proprietary blend of LED light spectrae coupled with our state-of-the-art technology..." Who can blame them? The market right now is soooooo tiny.

    In ten years we will all be laughing about the primitive approaches we are cobbling together right now. I have a flashlight in the door of my truck that is literally brighter than the HID headlights on my car. It's no larger than a D-cell flashlight. It exists not because there's a market for flashlights like that. It exists because each and every one of those display lights in every store in the mall uses 80% of the energy consumed to generate heat. The technology just trickled down. And quickly. Once the horticulture industry likes what they see, LED manufacturers will be tripping over each other scrambling to provide diodes to the fixture manufacturers. And then there will be a lobby pushing for tax credits for energy-saving technology adaptation. And that's commercial viability. Interestingly enough, that LED is a possibility right now. There are companies that compound specialty phosphors and others that specialize in specialty diode production. All you need is a spectral curve and the $$ for an order.

    I hope all this stimulates someone with more knowledge and understanding of the topic than I (not a high barrier) to weigh in and share some of that knowledge- if even on some of the biological basics. There's more than enough research out there on light and plant growth. What I'm hoping is that there's someone with a level of understanding that can offer guidance on the potential parallels between growing cucumbers in a cave and growing nuisance hair algae in a small box inside a dark cabinet.

    One other quick comment about emerging light technologies- The average greenhouse operator cares about what's in the light fixture above his crops as the average reef-keeper cares about what's in the fixture keeping his corals alive. They just want it to work. That's why alot of these "white papers" don't get into the specifics. The USDA funded research as well as published stuff from grad programs really does contain a remarkable amount of specifics. The key is transferring this to our particular species of desired algae.

    Frankly, I think if I could spend $3-400 on a proven fixture, I wouldn't have begun any of this. But I see the same approaches working in one place and failing in another, the light element intrigues me and I have a suspicion that the key to success in an ATF lies in a large part somewhere in that neighborhood.

    25-some years ago I tried macroalgae filtration system with very good initial success and then catastrophic failure. Being pre-Google, the resources I had were incredibly limited. It amounted to guessing what Dr. Adey did and what a very thinly populated public library provided. I liked the concept then and I still do. There's nothing more appealing than a completely natural process.


    Another good read.

    http://hortsci.ashspublications.org/...rint/43/7/1951

    Somewhere in the back of my mind, I recall reading about algae being biologically similar to various leaf lettuce varieties. This article addresses lettuce and also discusses white light.

    "Many previous studies indicate that even
    with blue light added to red LEDs, plant
    growth is still better under white light."

    The article also addresses some successes using supplemental green spectrum lighting. And while it doesn't refer to it directly, green is the section of the photoresponse curve that carotenoids react to.

    I did notice that one of the authors is one of the individuals involved with one of NASA's ISS experiments using LED's in grow light experiments. i have yet to run across anything published on that initiative.

  2. #2
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    Hello and welcome. You are right the LED thing compared to the MH is meaningless at best. Its late so I didnt read 100% of your info but I understand where you are coming from. I started this scrubbing thing when we only used the florescent tube then came the curly Q CFL which held promise due to size. A few others and I where the first to try the red 660nm LED thing and it worked better then the others mentioned in my case. Next we tried adding 445nm blue which was a huge improvement again in my case as well, and now I will be adding 417nm to it to see how this works out for me. Sounds like you have done a ton of homework on this subject. There are a couple folks out there that have done a lot of research and testing on this LED deal. There is one guy that goes my ace25, he is really sharp on the photosynthesis and LED deal. His knowledge has saved me and many others hours of research. I am sure if he sees this post he will respond. I started my business full-time almost two years ago so I kind of dropped off the radar on the scrubber/LED deal but I have been able to get back to the forums about 1-2 times a week now days.
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    Welcome.

    does practical application show that specific light spectrum isn't as crucial
    In my case, yes.

    These algae will grow with just one of the three photosynthetic compounds supplied proper light
    Apparently they might. Although the exact species and structure has not been examined.

    My concern is constructing something that will work OK but unbeknownst to me, is nothing more than a delayed catastrophic failure.
    More has been learned about old tank syndrome. One possible component -- metals buildup in the substrate -- can be reduced with a scrubber because algae consume metals.

    I know LEDs hold the most promise for algae propagation. But is success or failure a matter of what got randomly grabbed out of a parts bin?
    It's a matter of physical construction to provide algal attachment, air/water interface, flow, and ease of cleaning and no-mess reliability.

    Some of the literature I have read speaks to far red adding significantly to algae's co2 fixing and potassium uptake abilities.
    Might indeed be true.

    I think what we are confronted with is a particular limitation in available LEDs
    Probably not; it's just the difficulty of building the units.

    The main hurdle for aquariums is the construction and placement of the units. Differences of 200 or 300% effectivenes can be had by just moving things around a few cm. And ease of installation and cleaning are most important -- if they don't happen, nothing matters anyways.

    So the tens-of-percent improvement that could probably be had by spectrum changes are probably not worth the hassle, yet.

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    Thanks for the welcome and the response.

    I suppose I should more clearly restate what it is I am attempting to accomplish, as it's probably buried in the mess posted above. I am purely looking at light and its effect upon the growth of algae. I am making the assumption that in my hypothetical that in my model, all of the other variables, such as water flow and the physical construction and implementation of the scrubber are optimized.

    In short, if one were to take the best, most highest-performing and well established scrubber and, via the manipulation of the light spectrum presented to it, grow a stronger, more stable and more hardy algae.

    This interest stems from information provided to me from several "professionals" in the trade. More than once it was suggested to assemble a light source using 630nm diodes and "toss a couple royal blue's in there too". I found this contrary to some of the very basic reading I had done. I have a tendency to want to know the "why" that lies somewhere just beyond the "how".

    In short, I believe the following to be true-

    --Algae scrubbers work.

    --Algae scrubbers can be made to work in the highly-miniaturized application of hobbyist aquariums.

    --Algae is a very robust species.

    --The more robust and prolific the algae is, the more efficiently it will remove undesirable elements from its feed water.

    --The more robust and prolific the algae is, the more able it is to handle sudden, substantial increases in undesirable elements in its feed water.

    --The more robust and prolific the algae is, the less susceptible it is to competition from undesirable species of algae and to damage from external events such as power outages.

    And based upon that,

    --Making the assumption that a scrubber is constructed and implemented using best-known practices, and based upon significant research into the propagation of various algae, I believe that through the manipulation of light intensity and spectrum, algae can be grown with a result ranging, from "it grows" to "pretty good" to "maximally efficient/maximally bulletproof". For the sake of our discussion let's range this in a 1-to10 scale. 1 being "something is growing but I don't know what" and 10 being a thick, green mat.

    So, to cut to the quick here, if I could move from 4 to a 6 or 7 just by selecting the proper LED, and varying its intensity and photoperiod, why wouldn't I?

    In all the research I have read, algae is identified as being highly photoreactive at various light frequencies and substantially less at light frequencies just a very tiny bit above or below those optimal points. The thing is, different algae react differently. If one were able to understand more clearly the light spectrum the algae we seek to grow requires, we can make it grow in a more beneficial fashion. Think about this- what if the light you're using is better suited to the algae you don't want growing in your scrubber than it is to your preferred species? It's certainly possible.

    One of the first thoughts I had on this topis was on the compact fluorescent bulbs being used by many. The common thought on CFL's is to use 2700K. But which one? Each manufacturer arrives at 2700K differently. Color temperature is not an expression of spectral output. Color temperature is an expression of how the human eye perceives the colors of objects illuminated by that light. Each manufacturer arrives at color temperatures differently. One manufacturer may use a curve with a large peak at 660nm and one at 445. Those are known algae growth stimulation points. But what if another manufacturer arrives at 2700K with a different curve? You and I have pretty much the same setups and are doing pretty much the same things- including using 2700K CFL's. But yours works better.

    If you don't understand and consider every variable, you're basing your success on luck.

    My objective is to be able to refine my setup to where it operates in the most stable and most efficient fashion. I have always found that cleaning up a failure is usually more work and expense than doing the legwork up front. At the same time, all science is based upon failure. If you identify enough failure and then place that next to what is known and established, the solution typically presents itself very quickly. In our arena, and as far as I can tell, no one has done any significant research into the topic. But I believe there's enough information that's incredibly close to the subject that will allow us to stand on the shoulders of others and further refine our approach to this technology. I don't think I'm going to get to "10", but I'm pretty sure a 7 or 8 is do-able.

    My issue is this- I'm an engineer, not a PhD biologist. I think I know somewhat I'm reading. But I don't expect that I understand it any better than a biologist might understand my profession. My hope is that this conversation engages some people with a better grasp of the topic.

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    Welcome,

    You have some good questions

    The answers you will get here are based on trial and error from folks who have been using algae scrubbers for years.

    There are a lot of variables, the light spectrum from LED's is one of them, but waterflow, distance from the light source to the screens, type of scrubber used, the amount of feeding done, what animals are in the tank, and other variables can make a big difference.

    Like many here I have experimented with different light sources and have found something that works for me. Keep in mind that you can custom build a light source or you can buy something that will be in the range you need that will work fairly well.

    The proof is the algae growth you get and the reduction of Nitrate and Phosphates in your water by using this technology.

    I recommend taking at look at the threads here on the basics of how this works.

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    Thanks!

    Before I read everything available on light spectrum and algae, I spent a month reading about algae scrubbers. That's where this whole thing came from- the people who appeared to be doing everything right, just as others had experienced success with, but theirs wasn't working. There IS a reason. And it's disheartening to read about someone's frustrations and ultimate surrender.

    I am most certainly going to build a solution. That's based mostly on my belief that no one out there makes anything beyond a shotgun approach with a curve based on assumptions and an attempt to mimic MH lighting. And the more I read, the more I believe that while this mish-mash of lighting will certainly work and certainly grow algae, there are better ways to go about it. Researchers have proven that light at a certain spectrum when combined with another, different spectrum, can actually inhibit growth.

    I'm not searching for something that works. I'm searching for the absolute, best possible results. If what works was enough for all of us, we'd still have undergravel filters or wet/dry's (does anyone remember DLS?) I experimented with macroalgae scrubbing in the late 80's and experienced initial success and ultimate failure. At the time I wasn't able to investigate why as I found myself quite time constrained with a growing business and two babies. I retreated from the hobby for some time.

    What I'm working on right now is acquiring a sufficient quantity of available LED's ranging from 400 to 800nm. My intention is to fabricate a test fixture where I can experiment with various curves and photoperiods. I especially want to explore time-curve adjustments to spectral distribution over the entire photoperiod. This is what occurs in nature as well as what greenhouse operators are working on. Even people in our hobby are investigating this approach with corals. The concept of lights on/off seems short-sighted. Why would someone embrace such a natural-process oriented approach to water purification and integrate an approach so far away from that?

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    Well do start some tests and post them up

    Also don't forget about the intensity variable. You can read a little about it here:
    http://algaescrubber.net/forums/show...lumination-PCT

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    There has even been some info released somewhere about pulsing the LED's on and off every few milliseconds to achieve faster growth which would mean faster filter. I have been wanting to build a logic circuit to control a gate or solid state silicon relay device to accomplish this. There are some arduino boards out there that I could use to get this done. This showed huge promise in my opinion because I feel we could build a much stronger scrubber. I like your idea of testing LED's. I did a test with six 660nm on one side and the other had four 660nm and two 445nm on a 6x6 screen. The reasults on the red/blue side where much more as the algae mate was about 1" thich and grew several inches down into my sump where the all red side was only about 3/8" thick and only grew a couple inchs into the sump. I also installed the screen on the opposite side each time after cleaning so the red side would be on the red/blue side for the next cycle. I did this for a six month period with the same result every two weeks. As I stated before I want to add two 417nm LED's to the screen and compare this as well. I know its not any scientific test but its what I was able to do for my own research.
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    Quote Originally Posted by SantaMonica View Post
    Well do start some tests and post them up

    Also don't forget about the intensity variable. You can read a little about it here:
    http://algaescrubber.net/forums/show...lumination-PCT
    What I'm attempting befor beginning tests is ti identify some elements that are known to work and, more importantly, known not to work. I'm not the brightest guy, but I know enough to try to avoid the mistakes those that have come before me have made

    I gave the patent app a quick read. It obviously deserves a thorough review I'm interested in the approach of controlling process variables correlational to the appearance of the algae. From what I can deduce from reading, the majority of research quantifies performance by changes in water chemistry. Would it not be more effective to modulate your various parameters, whether they be flow, light intensity, spectrum additives, etc. based on easily measurable factors such as o2 or pH? Or am I missing something?

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    Quote Originally Posted by kerry View Post
    There has even been some info released somewhere about pulsing the LED's on and off every few milliseconds to achieve faster growth which would mean faster filter. I have been wanting to build a logic circuit to control a gate or solid state silicon relay device to accomplish this. There are some arduino boards out there that I could use to get this done. This showed huge promise in my opinion because I feel we could build a much stronger scrubber. I like your idea of testing LED's. I did a test with six 660nm on one side and the other had four 660nm and two 445nm on a 6x6 screen. The reasults on the red/blue side where much more as the algae mate was about 1" thich and grew several inches down into my sump where the all red side was only about 3/8" thick and only grew a couple inchs into the sump. I also installed the screen on the opposite side each time after cleaning so the red side would be on the red/blue side for the next cycle. I did this for a six month period with the same result every two weeks. As I stated before I want to add two 417nm LED's to the screen and compare this as well. I know its not any scientific test but its what I was able to do for my own research.
    Thanks for the input!

    I did begin reading on the pulsing light effect but it was late and I had reached my knowledge saturation point for the evening. It did look interesting, as did some of the material on far red lighting. Far red was being experimented with to simulate sundown-like effects in an attempt to stimulate the plant's competitive shade-avoidance mechanism.

    I also did see some information about the near-IR spectrum. Again, these articles deserve a less-cursory reading than what I did, but I was intrigued as to how carotenoids came into play. If I was reading it right, carotenoids play a significant role in preventing UV light from damaging the plant's cellular structure. And again, if I read correctly, carotenoids require a spectrum in the high-400 to low-500nm range for their development. I think I would want to know alot more about this effect before I implemented 417's- especially on an operating tank. if your algae isn't receiving the light spectrum necessary for carotenoid development, it may have a significantly compromised ability to fend off the UV. As I have gathered, algae will grow without carotenoids- they provide little in the way of photosynthetic nutrient to the plant. And while I have definitely seen curves that went somewhat below 445 and provided benefit, that benefit is certainly negated if the increased photosynthetic activity is offset by cellular damage caused by the plant's inability to cope with UV that stems from not receiving a complete light spectrum.

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