DIY LED wavelengths and total wattage

[MorganAtlanta]

Have people been successful with just 3W 660 nm reds, or is it worth adding some 630 nm reds and/or 455 nm Royal Blue?

Have people been using the same total number of watts of LED as the guidelines give for CFL, or can we back off the wattage a bit with LED since the light should be more efficient in terms of photosynthetically usable radiation?

[Ace25]

I am using a full screen and I am now only running 4 660nm reds per side, so with the driver, about 30w total to light both sides. Originally I was using 60w+ when I had 10 LEDs per side, whites though. I think 4 has the be the bare minimum though, but that was what I was trying to learn myself, what was the least amount I could use to achieve the same or better results than 26w CFLs. I think I am getting 2-3x better results with the LEDs than I was with the 26w 2700k CFLs even just using 4 LEDs per side (4 is needed to have good coverage on the screen), but I would bet if I added 2-4 more per side I would get even more growth. As it is now, I can only go 4 days tops between cleanings because the screen grows VERY fast and thick, even though I clean the screen very good each time, much cleaner than most people would recommend. On my other tank I also have an ATS and use 42w CFLs and I can easily go 2 weeks between cleanings if I wanted, it doesn't grow very fast at all.

Floyd is going to be able to tell us the answer on the other LEDs pretty soon. I really can't say if adding 630nm LEDs would really help that much, 640nm seems like it would help a lot more, but I have never seen a 640nm 3w LED. I don't think 455nm royal blues help at all, I think 420-425nm LEDs may help, but right now that is just a guess. Right now I think 660nm will provide a good 80% of the spectrum needed for algae, the other LEDs will add just a little.. "think" is the key word there, I do not know for certain at this time, but again, those will all be answered by Floyd pretty soon. I know I am anxiously waiting to see his results. I just know 660nm does indeed work very well by itself.

[tebo]

Ace25, a question:

You say that you are using 4 led per side, are those 3w leds?

What are the dimensions of your net?

Im asking because im about to buy the 3w Osram for my screen, my net’s dimensions are 46”x8”, i would like to know if 20 leds are enough putting 10 per side

thanks

[Ace25]

Screen is the standard 13.5"x10.5". Yes, 3w LEDs run at 750mA. I am thinking on a screen as big as yours, 12 per side is going to be needed.

[kerry]

Are you running a lens on these LEDs? If so what angle. I am planning a build to replace my CFL driven scrubber. Its 10G with a 2.75x6.75 horizontal sloped screen single sided. I was planning on two or three 660's with 80 degree lenses. I thought 3 might be overkill after reading you have 4 on you full size screen. I think I am going to be about 2 inches from my screen with what I have to work with.

[kerry]

After some more research I see the OSRM 660 does not have a lens offer at the rapidled site. ???

[MorganAtlanta]

Wow. Going by the standard guidelines, I'd expect a 13"x10" screen to use about 65W of CFL per side, but you are getting great growth with just one wavelength at less than half that wattage. Very cool. Now I've really got to go LED...

As for the other wavelengths, I was going by the chlorophyll numbers of peaks in A absorption at 453 and 660 and peaks in B absorption at 430 and 642. Based on this chart below, it looks like putting in at least some light in the 400-480 range would be helpful. I have some extra CREE 3W 455 nm LEDs laying around, so I'll probably throw them in.

[attachment=0:yeca7cib]absorption spectrum.jpg[/attachment:yeca7cib]

[Ace25]

Based on this chart below, it looks like putting in at least some light in the 400-480 range would be helpful. I have some extra CREE 3W 455 nm LEDs laying around, so I'll probably throw them in.

That was exactly my thinking as well... so I tried it, only to learn that Royal Blues not only did not grow algae, the algae seemed to die off with only royal blues. I was testing to see if Royal blues by themselves could grow algae, I tried mixing Red/Blue and noticed slightly less growth than all Red so I took it a step further and tried all blue. Algae turned to mush, didn't grow, and a gentle wipe of the finger would make it come right off. So after that experiement I came to the conclusion that algae does not have a preference for 455nm light, but I still don't have the answer for 430nm light.

As I learned there are a lot of other factors that go into photosynthesis besides just what the graph shows. Like in corals, corals have no way to regulate 660nm light, but it can regulate 455nm light, so while in theory 660nm light will grow corals, you have to be extremely specific on putting in the right amount of light without putting in too much or else the coral will die. There are 2 different areas for absorption, the lower and higher wavelengths, in corals if you give it too much 455nm it can take the extra light that goes beyond the max absorption and roll it over into a "storage" area in the 660nm area, kind of like an extra gas tank, but the flip side is corals do not have that same ability with 660nm, if you give it too much 660nm it won't put the extra into the 455nm area, it simply causes the zooxanthallea to leave the coral in turn bleaching it, and if nothing is done to correct it, the coral will die. The same thing can happen with too much 455nm as well in corals, but it takes a lot more since there is a mechanism in corals to put the extra light into storage so to speak. That doesn't mean anything with algae other than the fact there is obviously more to photosynthsis than just giving algae the light that the graph shows would be ideal.

[MorganAtlanta]

The 3W 430 nm LEDs are hard to come by, and expensive ($15/ea). If running all 660 nm works well, then I guess it doesn't make sense to bother with anything else.

[jnad]

Hello!

What about this panel (only 1 watt leds), will this panel work very close too the screen?
http://www.ledwholesalers.com/store/...&productId=421

jnad