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Blue LED lights for CPs


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#1 ifurita

 
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Posted 30 March 2012 - 02:32 AM

It may sound a bit silly, but can blue LED lights alone be used to grow CPs? I know that most LED light pannels use a mixture of blues and reds, but is it possible to just use blue alone with no other source of light?

I did try to use blue T5s which seem to work with Neps, but they do get some light from various places in the room, especially another tank using a white T5s next to it which I can't move away, so it isn't exactly a fair test.

#2 Zlatokrt

 
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Posted 30 March 2012 - 05:59 AM

I think it wont work. But i am sceptical even to blue/red panels and use only sources of white light with as full spectrum as possible. So you might get a good result and i might show wrong :-) Chlorophylles use mostly red and blue parts and they are the most important, but they are not the only molecules in plants, which absorb some light.
Regards
Adam

#3 Fernando Rivadavia

 
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Posted 02 June 2012 - 16:53 PM

He guys,

I've set up a Ping wall at my place (http://www.cpukforum...pic=17560&st=60) and want to add some lights. So this topic speaks to lighting questions I am currently debating. I am considering LED options, to save on energy in the long run. But I do not understand why LED systems for terrarium/ agroponics seem to often be composed of a combination of colors, whereas aquarium lighting is usually some sort of white light.

Please help me understand the different points of view here: white light X multi-colored lights.


Thanks,
Fernando Rivadavia

#4 mobile

 
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Posted 02 June 2012 - 17:22 PM

The idea is to increase efficiency by using LED colours targeted at the specific spectral requirements of plants, i.e. chlorophyll absorption bands etc. White LEDs will emit some wavelengths that are of little or no use to plants, so this is wasted energy.

#5 Fernando Rivadavia

 
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Posted 02 June 2012 - 17:25 PM

Yes, but does the theory work in practice with CPs (more specifically Pings)? Anybody know how this affects Ping flowering?

Thanks,
Fernando

#6 manders

 
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Posted 02 June 2012 - 18:01 PM

I've had several lowland neps under blue/red LEDs for a number of years (and also some ferns / orchids etc) all are doing quite well. I think you save about 50% of the electric for similar growth rates (compared to flourescent) hard to judge though. Never tried pings under LED.

#7 0rmus

 
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Posted 02 June 2012 - 18:12 PM

I recently made a switch from a '125W 6500K CFL' to a '120W Quad Array LED' light.

@ifurita
Can you grow a CP using just blue LEDs? - Yes, though it may not grow as well as an equivalent fluorescent or multi colour LED grow light as the plants would only be able to photosynthesis using one narrow band of light.

@Fernando Rivadavia - Plants generally need light of the red to orange and blue to white colour range to photosynthesise. Plants also favour different colours for different area of development, for example, red to orange spectrum is generally thought better for fruiting or flowering plants and blue to white is though to be better for vegative growth. By individually targeting these areas of light, LED grow lights are able to output more ''usable'' light per wattage than fluorescents which output a much broader band of light, much of which isn't useful to the plant. By outputting an array of 'usable' colours the LED light becomes more versatile for different stages of a plants development.

How do LED lights perform when it comes to growing CPs? So far my experiences are pretty good but i have seen no major advantages to my 120W LED rig to using a 125W CFL in terms of plant growth and health.

Hope that helps.

Edited by 0rmus, 02 June 2012 - 18:14 PM.


#8 Fernando Rivadavia

 
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Posted 02 June 2012 - 19:04 PM

Thanks for the info guys!

Since I already have some natural light coming through the window, I guess adding blue/red lights would be best (missing wavelengths may be compensated for by the natural light?).

I've been searching online for the past hours, looking through eBay, Amazon, and LED company websites. Seems like the blue/red or multicolored panels are always square or wide rectangular in shape. Does anybody know of a long fixture type setup with blue/red/mixed LEDs? I have to cover the whole ~260cm / 102 inches of Ping wall.


Thanks,
Fernando

#9 manders

 
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Posted 02 June 2012 - 19:04 PM

0rmus, What plants have you tried them with and what where the four wavelenghts in your light? Its really interesting to see other poeples opinions on LEDs with so little real information around. One thing though do you mean white light or uv? White doesnt exist as a unique wavelength but is a mix of everything else.

Anither thing is that typically a 125W LED setup would be consuming ~70w of power because they are typically sold by the number of nominally 1W (or 3W) leds, not by the actual power consumption. Typically the 1W LEDs only consume 0.6W each to extend their life.

Edited by manders, 02 June 2012 - 19:12 PM.


#10 0rmus

 
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Posted 02 June 2012 - 21:12 PM

@ Manders

Specification:

Brand: PRAKASA™
LED Configuration: 112 x 1w LEDs
Power consumption: 110w
Lumens: ≥4200 Lm
Lifespan: 50,000 Hours
Color: Red/Blue/Orange/White
Wavelength:
Red: 630nm, 77 leds
Blue: 460nm, 15 leds
Orange: 610nm,10 leds
White: 15000-20000K, 10 leds
Suggested Lighting Area: 1 - 1.5 m2
Size: Ф 400 x 212 x 62mm

Posted Image
Posted Image
Posted Image

Yes you are right, white in this case is a mixture of colours from 15000 - 20000K… Seems kind of pointless. I guess they throw it in as a 'cover all' wavelength.

I have grown VFT's under the LED rig for two days under a month. I haven't noticed much difference in speed of growth compared to the 125W CFL but the LED light has definitely produced more colour in my plants. The very cool temps caused rot issues on a couple of my VFTs as it didn't dry off the top soil. I’ve since added a PC fan to compensate.

#11 manders

 
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Posted 02 June 2012 - 22:52 PM

I agree, i've had some neps colour up very nicely under LEDs. Also the lack of heat from the LEDS does mean having to adjust growing conditions in some other way as you mention. I had to add a heater to one of my terrariums for example.

If you measure the power going to your LED, i would guess it will read quite a bit less than 120W, the chinese manufacturers stick any old rubbish on the label. I have a few similar units, although '90W' rather than '120W'.

Edited by manders, 02 June 2012 - 22:52 PM.


#12 Fernando Rivadavia

 
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Posted 03 June 2012 - 06:26 AM

Today I saw some cheap LEDs at a local fish shop, here's the same one on Amazon:

http://www.amazon.co...TF8&me=&seller=

Anyone have experience with these?


Thanks,
Fernando

Edited by Fernando Rivadavia, 03 June 2012 - 07:28 AM.


#13 manders

 
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Posted 03 June 2012 - 08:14 AM

Never tried it Fernando but it does say fish only tank and its only 11W, so i doubt plants would grow under it. You would need a much hgher wattage.

#14 0rmus

 
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Posted 03 June 2012 - 12:25 PM

@ Fernando Rivadavia - That 11W LED light is insufficient for anything more than maybe tiny seedlings.

@ Manders - My light is made in the UK and the power consumption is 110W. I got it for £40 off someone who preferred using HPS. Its a nice rig but at the mark up cost, its a lot to pay for a little extra colouration in my opinion.

#15 Fernando Rivadavia

 
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Posted 03 June 2012 - 18:04 PM

Hmmm... true, 11W is not much. But like I said above, the wall is facing a window, so there's already some natural light. The LEDs would be a compliment. Thus, I wonder if it would be enough....

Thanks,
Fernando

#16 0rmus

 
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Posted 03 June 2012 - 19:09 PM

In my opinion Fernando Rivadavia, the amount of 'boost' you would get from that light would not make it worth it. I would recommend something a lot more powerful.

#17 Fernando Rivadavia

 
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Posted 03 June 2012 - 19:29 PM

In my opinion Fernando Rivadavia, the amount of 'boost' you would get from that light would not make it worth it. I would recommend something a lot more powerful.


You're right, probably not worth it... Darn, I was excited to see a cheaper LED panel, but I guess I'll just have to go for one of the expensive ones...


Thanks!

#18 manders

 
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Posted 03 June 2012 - 21:48 PM

0rnus, did you actually measure the current?

#19 Zlatokrt

 
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Posted 04 June 2012 - 13:17 PM

Fernando, i think, that better would be some red-blue panel, since the minor, less important, wavelenghts come from the window in the sufficient amount. You need only additional lights and targeted efficient leds will spare some energy costs. (On the other hand, as the only source of light, i would recommend white leds because of their spectral distribution similar to natural light, better than fluorescent tubes. But this is not your case.)

That 11 W panel might work, but it looks like it is composed of white and blue leds - not the best for you. It is designed not only to light the plants, but also to make them look nice in the aquarium (same for the fishes...). What is the size of your ping wall? I would guess 2 m x 0,5 m? You would need several of those 11 W lights. Five or six i think.

The 120 W panel Ormus posted here looks very good, although the wavelengths could be better, closer to the chlorophyll absorption peaks (cca 430, 450, 630 and 660 nm). But it is not the best shape for your wall, it is centered on a compact area (or is it not? Ormus could tell us). The best for you would be a line source, your wall is quite long and narrow. I personally would try to get some powerful led stripe with red leds, then the same one with blue leds and maybe i would think about some other colours, but the red and blue should be the most important. Then i would mount them on some aluminium profile in several lines (depending on the lights power), which would hang next to the pings lighting on them. The question is, where to get powerful led stripes with good specifications (wavelength, power and life span), so far i have only used white leds (with good experience i must say).
Good luck!
Adam

#20 Fernando Rivadavia

 
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Posted 04 June 2012 - 17:04 PM

Hello Adam,

Thanks for your input, I agree that blue/red would probably be the best to complement the natural light coming through the window.

Those 11W panels are ~48" (120cm) whereas my Ping wall is ~103" (260cm), so I would only need two panels. But I agree that long LED strips of the right colors may be the best way to go. Haven't found many options on the web though... Here's the most promising I've seen so far:

http://www.ecoxotic....ps-24-watt.html

They have 48" 24W LED strips for $99 each, with several combinations of white, blue & magenta. Looking at their color chart (http://www.ecoxotic...._chipGraphs.pdf), it seems like a mixed blue/ magenta strip would cover all the good wavelengths.

Looking at p.4 of the Ecoxotic Stunner light manual (http://www.drsfoster...StripManual.pdf ), it seems that I can attach two of these 48" 24W strips to a single power supply. The power supply is $36.95 and a 2-way splitter is $7.95 (http://www.ecoxotic....ccessories.html ).

I've heard of a possible spotlight effect commonly mentioned for LEDs, and I don't want the light to be focused on a narrow strip along my Ping wall. It seems like lenses are often put on the LEDs to spread the light (not sure I understood this correctly on a website I read). I noticed on my Reefbrite aquarium LED fixture that it uses reflectors to help spread the light better over a ~90 degree angle. I don't know if this is the same thing, but I noticed that Ecoxotic also offers reflectors to "double the light output". These are not very expensive and may be worth it.

So if I was to buy 2 Ecoxotic 48" Stunner LEDs strips (blue/magenta), 8 Ecoxotic 12" Stunner reflectors, + the transformer and 2-way splitter, I'm looking at an investment of $261.55 + tax & shipment (if I bought it from their website - I have seen the same items slightly cheaper on other websites).

Argh! Not as cheap as I was hoping, but I just have to convince myself that it'll save me money in the long run on electricity bills and not having to switch out bulbs once a year.

Anyway, I appreciate any suggestions/correction to what I wrote above, before I make a decision...


Thanks,
Fernando Rivadavia