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[APD] APD] LED lighting --a wrench in the gears....



Gomer / tony - you're over-analyzing!

NASA's shuttle grow booth uses only 670nm and 470nm (I think I read it was a 4red:1blue ratio) for their growth experiments. While we know it would be GREAT (or maybe not so) if a LED could put out exactly 670nm - in practice there's a nice curve when you look at the specific wavelengths put out by each led - so while 664 and 662 are the 2 major chlorophyll peaks - chances are a 670 or so LED is going to encompas both (probably less for chlorophyll B)

If one was going for a PURELY grow lighting - then yes you'd probably want to hit those peaks with specific LEDs to those wavelengths. But as we generally have fish in our tanks, I think their needs become our priority - thus we use at least some white light - to give them some sense of normality. Between the White LEDs and in my case the reds - those wavelengths must get hit well enough to cause pearling.

Pictures - yes as soon as my digital camera gets repaired or replaced. I'll see if I can get something visible with the webcam (so far its managed to get a blue-white glow - and thats it)

Andy

Date: Mon, 05 Jan 2004 15:22:28 -0800
From: "Gomer Gomer" <iegomer at hotmail_com>
Subject: [APD] LED lighting --a wrench in the gears....
To: aquatic-plants at actwin_com

A couple things to consider. If you are looking for growth and not just
lighting a tank (which I think we all want)...then just any ol red or blue
won't cut it. Chlorophyll A and B both have absorbtion bands that are not
easily matched with LEDs (or atleast the ones I can find). Also, you NEED
blue for more than just growth. Blue is what the plant uses to in order to
know what direction to grow.

http://www.biologie.uni-hamburg.de/b-online/ge24/03.jpg

..everything else is wasted as far as growth is concerned.

-_Tony

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