LED Lighting and Robust Algae

I found a little info on the pulsing effect however its not the one I was looking for, still informative though, here it is: https://mywebspace.wisc.edu/tsharkey...ght%201995.pdf .
I have great success with four 660nm and two 445nm on each side of a 6"x6" screen. I have read about the UV 417-ish nm and coral development vs using only white and the royal blue and wondered if it would apply to my algae so I am going to try. I have plenty 417nm laying around after a DIY Tank Display LED build with about 1:1:1 ratio, white 20,000K:417nm:445nm and only two red 660nm. I figured I could throw two of the UV on one side of my screen and see what happens after a month or so. I was fearful of UV damage but I figured its worth a try, and I love to tinker and build stuff so it keeps me occupied in my free time. I have never seen anyone post anything about using UV on a scrubber so I figured I would give it a test.

My guess is that in using a full-spectrum bulb, the blue-green spectrum needed for carotenoid development was present. I would be careful with the 417 unless you're in a situation where you can afford to lose or severely compromise the algae. Being a pale-a$$ed northerner, I know just how fast IR can cook unprotected tissues. if carotenoids are, as I suspect, nature's sunscreen, I would proceed slowly, with brief amounts and working my way up to longer doses.

I will see if I can find the research on light pulsing and post it.

I have my reservations about the UV but I can afford to loose one side of a screen. The red/blue can recover very quickly. Also I have noticed that the algae in my tank that developed when my scrubber pump developed a restriction has been shrinking since I removed the restriction but, since I have added the UV to the display LED this algae has been shrinking considerably slower. I am not sure if its due to the UV or not, its just something that I have noticed.

Biologists use all sorts of measurements including O2, pH, chlorophyll spectral sensing, etc.

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Originally Posted by kerry

I have my reservations about the UV but I can afford to loose one side of a screen. .

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In the late 89's/early 90's when I was very involved in the hobby, it was very difficult to acquire much information at all. The internet has certainly made information gathering so very much more efficient. Nonetheless, even what was generally available was not very in-depth, as most of it came form magazines. But back then, the prevailing wisdom was to, as closely as possible, what occurs in nature should be duplicated in the captive environment. Obviously that's not entirely possible, simply because of scale and processes virtually incapable of duplication (Unless you have room for a 100-million gallon sump) Not a very scientific approach, but certainly an elegant approach from a simplistic perspective. And understandably, not everyone sees their reef tank as a giant science experiment. Some are happy to enjoy it as a pet-keeping experience. So if you can get there by using, for example, a metal halide bulb that has a spectrum virtually matching natural sunlight, not many had interest in dissecting the functional effect of each NM of bandwidth.

Ultraviolet light is certainly one of those elements. Everything that's alive today evolved from something else. Not only do species survive by developing protections against a myriad external substances, forces and effects, their evolution has also provided them with the ability to use those factors to their benefit. I'm fairly certain that research exists on macroalgae's use/need of UV light. We know for sure that nature has provided a way for algae to protect itself from UV. I have no doubt it derives some advantage fro that exposure.

While I don't wish you to experience failure with your UV experiment, it certainly would be interesting to see if your algae survives/thrives/flat-out croaks due to UV exposure after it never being exposed to blue/green light.

CTS,

you make a valid point that not all LED's that say they are royal blue or red are actually the wavelengths that are optimum for algae growth.

Something that says it is a 660nm may be in the range but not exactly. I suspect like you do that a lot of the problems some people have are because their lights are not the same.

I have used CFL as well and found that they work. Probably because they have the range of light needed for algae growth.

I found that LED fixtures are easier to deal with in the construction of a waterfall scrubber for a number of reasons. The energy used is much less, and you don't have problems with heat like you do with CFL bulbs. I also found CFL's need to be changed often as the spectrum shifts over time, while you don't have to change LEDs unless they short out [another story].

I have been working to come up with an optimum solution for my tank. Still in progress. I bought some 30 Watt light fixtures that I found on ebay. They say they are 640 to 660nm with some blue as well.

I am getting good growth but like Santa Monica has said in another post, other factors are also critical as well such as the amount of water flow, the way your screen is roughed up, the distance from the light source to the screen, how often you harvest the algae, and the intensity of the lights.

Keep in mind that growing algae is only a means to an end here. You do this to provide natural filtration to your tank to remove stuff through exporting nutrients by harvesting algae.

Like the old saying, the Devil is in the details.

With LED's you have dominant wavelength and luminous flux. The LED manufacturer sorts these into sub-categories. They call that BINNING.

If you look at the Luxeon bins, your "royal blue" diode could have a dominant spectral peak anywhere from 440nm to 460nm. On top of that, the diode could have a luminous flux bin that can vary by 20+%. That means, one diode is 25% more efficient with the same power input which equates to 25% more output. So unless you know the binning your royal blue diode could have virtually no output at 445nm, the somewhat accepted sweet spot for that end of the spectrum. Even if you got a 455 or 450 bin but your output is down by 25%, you could be missing the boat. And if algae, as much research suggests, responds better to specific spectral peaks, a particular royal blue diode might be doing absolutely nothing. So a guy that doesn't know this because a fixture manufacturer doesn't tell him is having lesser success, he's bound to be frustrated. He's doing all the right things, right?

CFL's work, just as metal halides, simply because of the shotgun approach. You get with most of the warm whites a very broad band on the red end and typically a nice peak around 450. But, as I posed earlier, all CFL's aren't equal. One manufacturer gets to 2700K in different ways than another. I attached below the curves for the Sylvania 2700K and below it, their GroLux bulb. If you look at the spectral distributions, you'll notice large peaks in all the areas being spoken about, including the near IR. Honestly, I couldn't tell you if those bumps down low are actual engineered in attributes or remnants of the mercury arc. I'd bet the one down around 365 is either that or a side effect of the phosphor selection. One other thing- look at the bumps just below 550. I don't think they're there as the result of an error.

One other thing about the use of CFL's. Water and AC current over 40 volts doesn't mix. I deal with the NEMA and IEC construction requirements every day and what I see in some of these applications downright frightens me. It's one thing to have a power strip above and beside a sump in a cabinet bottom, but an unrated fixture above, let alone inside of a water containment vessel is simply not a good idea. The proper IP68 or NEMA Type 4/6 fixtures would cost about as much as a good used car. If you feel you must use this approach, PLEASE install a HIGH QUALITY GFCI device. Not one of those one's built into the end of an extension cord or power strip. And test it every time you get in the cabinet. (Preaching- /off)


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Originally Posted by CTS90

In the late 89's/early 90's when I was very involved in the hobby, it was very difficult to acquire much information at all. The internet has certainly made information gathering so very much more efficient. Nonetheless, even what was generally available was not very in-depth, as most of it came form magazines. But back then, the prevailing wisdom was to, as closely as possible, what occurs in nature should be duplicated in the captive environment. Obviously that's not entirely possible, simply because of scale and processes virtually incapable of duplication (Unless you have room for a 100-million gallon sump) Not a very scientific approach, but certainly an elegant approach from a simplistic perspective. And understandably, not everyone sees their reef tank as a giant science experiment. Some are happy to enjoy it as a pet-keeping experience. So if you can get there by using, for example, a metal halide bulb that has a spectrum virtually matching natural sunlight, not many had interest in dissecting the functional effect of each NM of bandwidth.

Ultraviolet light is certainly one of those elements. Everything that's alive today evolved from something else. Not only do species survive by developing protections against a myriad external substances, forces and effects, their evolution has also provided them with the ability to use those factors to their benefit. I'm fairly certain that research exists on macroalgae's use/need of UV light. We know for sure that nature has provided a way for algae to protect itself from UV. I have no doubt it derives some advantage fro that exposure.

While I don't wish you to experience failure with your UV experiment, it certainly would be interesting to see if your algae survives/thrives/flat-out croaks due to UV exposure after it never being exposed to blue/green light.

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I am still keeping the four 660nm and the two 445nm on each of both sides but I am going to add one 417nm to one side for a few weeks or less if its an obvious failure. The 417nm will just be an addition to what is there already for this experiment.

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Originally Posted by kerry

I am still keeping the four 660nm and the two 445nm on each of both sides but I am going to add one 417nm to one side for a few weeks or less if its an obvious failure. The 417nm will just be an addition to what is there already for this experiment.

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I think you're going to know where you're at pretty quickly. Just like with sunscreen- you can stay out in the sun all day if you effectively block UV, but if you haven't seen sun in awhile and you go out bare at noon on a cloudless day, in a half hour you're cooked. I would start using 15 minute increments moving up every couple days. That way you can gauge effect a bit better. Turning it on and checking next week will only let you know that UV will cook algae. We already know that. The question is how much is beneficial and how much is detrimental. Using one will concentrate the effect to one spot so the effect will begin on center and distribute outward. It will give a good visual comparison.

If you can get your hands on a green around 480nm, that would be a nice mix into your experiment.

http://i38.photobucket.com/albums/e1...ps4f05d036.png

I have a single driver and a timer I was going to put it one. I figured I was going to start 15 minutes at time, once in the morning, noon, and then later afternoon. I figured if this was to much I would know very soon. I might get it done this weekend.
I have thought about a green to but I dont have those just laying around and I dont have to order for awhile as you can see by the pic below. When I order next I considered getting a handful of green.
My 14"x9"x2" LED storage case.
http://i1164.photobucket.com/albums/...pshvpgiszr.jpg