# LED's for plants?



## ljs (Dec 15, 2011)

So, I'm setting up my 180 as a planted tank. Are people having success with LED's for plants? If so, can any recommend a good fixture?


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## Daniel L (Dec 6, 2010)

*I've had only good experiences*

I am currently using 9 Cree XP-G 3 Watt LED's with 45 degree lenses in a DIY fixture over a 16" deep 40 gallon tank and am very happy. They can be dimmed, add a beautiful shimmer, and consume less power than compact fluorescent or metal halides. Also, they where actually relatively cheap (considering that they will hopefully last for five years or more, I spent about 200 USD for all the parts).

There are quite a few discussions on this forum that can provide more info, I guess the main question is if you want to go with a commercial product or are happy to build something yourself.


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## matty26 (Feb 25, 2011)

diy ares the best. No commercial fixture matches up. If you don't want to do it yourself try and commission someone on here. You'd be helping out a fellow hobbyist and getting a great fixture.


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## talontsiawd (Oct 19, 2008)

I have yet to find a good LED fixture with the proper light spectrum for plants. Almost everyone on the board is using DIY fixtures. I have seen some people using some off the self ones but only in short tanks. Most LED fixtures on the market right now are really not that powerful, outside some Marine specific ones


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## Rockhoe14er (Jan 19, 2011)

I built an LED fixture and i love it. I will say their are commercially available ones on the market but they can get really expensive. I also know some people commission others on this site to build them one. Or if you like to build one yourself it's a really great project to pick up.


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## zergling (May 16, 2007)

My low-light 7.5gal cube is doing pretty well with the Archaea 30cm LED light. Slow growth, sure, but that's exactly what I wanted in that tank


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## Algae Beater (Jun 3, 2011)

i have numerous tanks under LEDs and love the growth!


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## Hoppy (Dec 24, 2005)

Light is the same whatever the source is, as long as the PAR is the same. My DIY LED lights have worked very well for me, but I'm still not as happy as I would like to be with the appearance of the tank with the LED light. One has half cool white and half warm white - too yellowish for me. The other is just cool white, which washes out some colors. Now that I know more about making those lights I would make any next one with two colors, and separate dimmable drivers for each color so I could adjust the color to please me. But, the plants do fine in any case.


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## WingoAgency (Jan 10, 2006)

You can track the progress of this tank


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## demonr6 (Mar 14, 2011)

Nice work there on the lights. Much as I would love LED's I would most certainly either burn the house down or take 3 years to complete the DIY project. Plus I don't want to spend $400 on lights..


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## moze229 (Dec 10, 2011)

This is kind of a soapbox, but I hate the fact that we've all been accustomed for so many years to using wattage as a brightness indicator. Until just a few years ago this was fine because you only had incandescent light to deal with. All 40 watt bulbs for example were the same brightness, so using the bulbs energy usage as an indicator was an easy, quick way to determine a light factor. But now with florescent, compact florescent, LED, halide, incandescent - you just can't do that anymore. And to compound this, manufacturers are still using wattage as a marketing tool. The first thing you see on a package, regardless of bulb type, is the wattage. This may be partly due to the growing concern for power consumption. 

I grew up using wattage as a determining factor on bulb brightness. Now I have to learn fifteen different factors of brightness by bulb type. When I go to the store and pickup those new CF bulbs I have no idea what I'm getting half of the time. I know halide pretty well, and I thought I knew florescent until recently.

I wonder how long it will be before we can just go ahead and standardize bulb brightness by using lumens, or candle power or something? That would not only help us as aquarium people, but everyone else as well.


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## kingfisherfleshy (Jun 4, 2010)

I as well am looking for solutions to get LED onto my 10g planted as well - I would love to have enough PAR to go to pressurized co2 as well.

Would two archaea work maybe? That would only be $120 or so...I currently run 2x 18w CFL


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## Optix (May 31, 2011)

Hoppy said:


> Light is the same whatever the source is, as long as the PAR is the same. My DIY LED lights have worked very well for me, but I'm still not as happy as I would like to be with the appearance of the tank with the LED light. One has half cool white and half warm white - too yellowish for me. The other is just cool white, which washes out some colors. Now that I know more about making those lights I would make any next one with two colors, and separate dimmable drivers for each color so I could adjust the color to please me. But, the plants do fine in any case.


does that "distort" par values or color spectrum in any way or is the decrease linear?

with that method...couldnt you buy say 3 (left, right, middle) high powered LEDs (instead of the usual array we see) suspend them high for good/uniform coverage and then just dim them til you get to an acceptable par value?


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## tentacles (Nov 28, 2011)

It definitely would change the PAR as you brightened or dimmed red and blue, but I'm not sure the plants would notice. Is there that much diffference going from 6500k to 8000k?

If all you're looking for is a certain PAR value, there's no reason you couldn't use three high power emitters (like 8800 lumen bridgelux or something). I think you'd just play it like MH, space them accordingly with appropriate optics or reflectors. 

For tricolor mixing setups, there are things like this: http://www.cutter.com.au/proddetail.php?prod=cut1025 with RBG LEDs. Keep in mind those things are sub-quarter sized, just over 3/4". Optics are available that fit on those as well. I have NO idea what kind of lumens you end up with that sort of setup, though. I think I've also seen somewhere RGB+W (4 emitters on a board).


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## rbarn (Mar 21, 2009)

Ecoxotic now offers a 6,500k "freshwater plant" LED module made up of 12 - 1W LED's
Run a little over $100 with power supply

The also have RGB modules.

http://www.ecoxotic.com/aquarium-led-lights/panorama-modules/panorama-led-modules.html


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## Hoppy (Dec 24, 2005)

Optix said:


> does that "distort" par values or color spectrum in any way or is the decrease linear?
> 
> with that method...couldnt you buy say 3 (left, right, middle) high powered LEDs (instead of the usual array we see) suspend them high for good/uniform coverage and then just dim them til you get to an acceptable par value?


Because I have access to my local aquatic plant club's PAR meter I would calibrate a light such as this - run it at various settings of the dimmers and measure the PAR for each one, so I could dial in the PAR I want. LEDs have a much more nearly black body spectrum than fluorescents have, so I'm not concerned about any changes in the spectrum from dimming them. I'm concerned with PAR only.

There is no one "best way" to use LEDs to light a planted tank. You can use a lot of low power LEDs spread out over the top of the tank, or you can use fewer higher power LEDs in a row or two rows across the top of the tank, or you can use a few very high power LEDs as if they were individual flood lights or spot lights. And, of course you can use a LED light sitting on top of the tank or suspended at any distance you prefer above the tank. All of this applies to DIY lights. With ready made lights you are more limited.


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## mcqueenesq (Aug 29, 2011)

kingfisherfleshy said:


> I as well am looking for solutions to get LED onto my 10g planted as well - I would love to have enough PAR to go to pressurized co2 as well.
> 
> Would two archaea work maybe? That would only be $120 or so...I currently run 2x 18w CFL


Wingo's lights are really nice. What are you growing? I have a Marineland Doublebright over a 10 gallon that is growing low to medium light plants well enough. I also have some Aquaray Grobeams over a couple emersed tanks. They are much, much brighter.


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## sockfish (Jul 11, 2007)

*LEDs and Lumens*

OK. I have a 30g I want to set up and I was looking at this online: 

Marineland Double Bright LED Lighting System. The write up lists Lumens only and it is 600 lumens. I don't have a PAR-Meter-Thing. Can anyone tell me if this would be sufficient for growing medium light plants?

Thank you,

sox


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## WingoAgency (Jan 10, 2006)

kingfisherfleshy said:


> I as well am looking for solutions to get LED onto my 10g planted as well - I would love to have enough PAR to go to pressurized co2 as well.
> 
> Would two archaea work maybe? That would only be $120 or so...I currently run 2x 18w CFL



Never used the archea before so no comments on that.

In general, if done properly, 12W of LED with lens can send the PAR to 60-90 for a 10G

I probably will do a RGB version for the 10G this weekend and I will report back the par results


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## Hoppy (Dec 24, 2005)

sockfish said:


> OK. I have a 30g I want to set up and I was looking at this online:
> 
> Marineland Double Bright LED Lighting System. The write up lists Lumens only and it is 600 lumens. I don't have a PAR-Meter-Thing. Can anyone tell me if this would be sufficient for growing medium light plants?
> 
> ...


That specific Marineland Double Bright light will give you only low light for a typical 30 gallon tank, but the 36-48 inch long one will give you medium light. If your tank is the 12-13 inch front to back depth tank, one of those may light up the entire substrate well enough, but if it is the 18 inch front to back depth tank, you will need two of them spaced a few inches apart to cover the whole substrate. This is based on http://www.marineland.com/uploadedFiles/Marineland/11078iMLLEDCharts.pdf


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## Optix (May 31, 2011)

Hoppy said:


> Because I have access to my local aquatic plant club's PAR meter I would calibrate a light such as this - run it at various settings of the dimmers and measure the PAR for each one, so I could dial in the PAR I want. LEDs have a much more nearly black body spectrum than fluorescents have, so I'm not concerned about any changes in the spectrum from dimming them. I'm concerned with PAR only.
> 
> There is no one "best way" to use LEDs to light a planted tank. You can use a lot of low power LEDs spread out over the top of the tank, or you can use fewer higher power LEDs in a row or two rows across the top of the tank, or you can use a few very high power LEDs as if they were individual flood lights or spot lights. And, of course you can use a LED light sitting on top of the tank or suspended at any distance you prefer above the tank. All of this applies to DIY lights. With ready made lights you are more limited.


Im asking the question unclearly

what I mean is...is a 10W LED @10" running at 50% the same as a 5W @ 10"? I was thinking of distorting spectrum as in if you take a NO bulb and overdrive it...it distorts spectral output (probably not enough to be an issue for plants)...I mean a 10W LED is designed to run at 10W...so thats why I wonder if the drop off in PAR is linear --like we assume the Lumens would be

which brings up another question...are Kelvin temps the same from LED to LED or is it an average (like typical flourescents)?

Im quantifying "best" as the most economical here...wouldnt buying 3 high powered LEDs be cheaper than say 9 lower wattage ones?...I would consider buying 7 (one of each color, ROYGBIV) high powered LEDs (and dimmer for controlling visible color output and PAR that way) as ideal

or a few high powered LEDs and then a smaller array of low powered, color LEDs (moonlight grade) to enhance visible color...tho more than likely, they would be overpowered and washed out

I remember you talking about something similar before...

man, I really need to start a fish tank prototyping fund to do some of the things I think of...maybe next year:icon_frow


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## Hoppy (Dec 24, 2005)

White LEDs are usually rated not by color temperature in degrees Kelvin, but by chromaticity, a more complicated way to describe the color of the light. And, different bins of the same basic part number LED can have considerably different chromaticity ratings.

A 10 watt LED running at half power could produce a very different PAR than a 5 watt LED running at full power (at the same distance). It all depends on the specific specs for each LED. The drop in lumens or PAR is not linear with a drop in power. At higher powers the efficiency of the LED drops off.

Before you can judge which LED configuration is cheapest you first have to define what you require the lighting to be. If you want uniformity of light over virtually the whole substrate, you can't do that with just 2 or 3 LED, whatever their power rating or optics used is. If you want a very obvious shimmer effect, you won't get that with lots of low power LEDs spread out over the top of the tank. If you want a minimal difference between the light intensity near the water line and near the substrate, you can't do that with just a few LEDs unless they are hanging way above the top of the tank, possibly requiring more power. If you want to fine tune the color you need 2 or 3 different color temperature LEDs in quantity, each with their own dimmable driver. If you don't want to see big beams of light or big spots of light on the substrate, you can't do that without using a significant number of LEDs, not just a few. Etc.


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## Optix (May 31, 2011)

so If I understand correctly...the "best" design -in terms of flexibility in design and operation

...would be an array of low powered LEDs w/ dimmer control circuits

good to know


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## WingoAgency (Jan 10, 2006)

Optix said:


> so If I understand correctly...the "best" design -in terms of flexibility in design and operation
> 
> ...would be an array of low powered LEDs w/ dimmer control circuits
> 
> good to know




Depends on what you like the light to do for you. The low powered LEDs design will not give you shimmer effect.


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## Optix (May 31, 2011)

personally, growing plants would take priority over aesthetics or water effects


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## Hoppy (Dec 24, 2005)

For growing plants the priority is having the appropriate amount of PAR. Next, in my opinion, is having that PAR be as near uniform from top of tank to bottom of tank as you can get it. And, last would be having it be as uniform over the whole substrate as you can get it. That would lead you to either hanging the light at least as high above the top of the tank as the tank height - 24 inches above a 24 inch high tank - or using a very large number of LEDs spread out over the whole top of the tank. The latter is tricky because really low power LEDs are so inefficient they can't provide the PAR you need. And, the most efficient LEDs are so powerful you can't use a large number of them.

But, all of these complications are why playing around with LEDs is such fun.


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## Optix (May 31, 2011)

I still think a relaxation method in ms excel could work wonders for initial planning

and i mean low end, of high powered LEDs (1-3W)


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## Hoppy (Dec 24, 2005)

Somebody is very likely to come up with a pretty simple way to pick a good LED configuration to achieve what ever someone wants. But, I haven't found a way to do that yet.


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## yegak (Jan 6, 2011)

Maybe this will help someone figure out a good configuration for LEDs.

http://www.trashboard.de/wp-content/uploads/illumination.swf


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## Hoppy (Dec 24, 2005)

yegak said:


> Maybe this will help someone figure out a good configuration for LEDs.
> 
> http://www.trashboard.de/wp-content/uploads/illumination.swf


What does this do? If my computer is loading it correctly it does nothing that I can understand.


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## Optix (May 31, 2011)

it is baically a geometry program that shows a 2D representation of light spread and overlap

...change the numbers around on the right and youll see


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## tentacles (Nov 28, 2011)

Optix said:


> and i mean low end, of high powered LEDs (1-3W)



You have to watch out, the cheap 3w LEDs put out about 50 lumens/watt vs 100-150 for a Cree. So the cheap ones are like 140-180 lumens @ 3w, the better cree are over 300 @ 3w (and 400+ at 5w) Also, if you read the fine print, the cheap chinese chips lose like 2% luminance in the first 2000 hours! The cree chips, if driven at 700ma or less, actually exhibit HIGHER than initial rated luminance after 6000 hours, then it begins to decline slowly. The cheap 10w 20w etc emitters are somewhat better efficiency, like 70-90 lumen/watt, but I expect they wear out pretty bad. My guess is that the cheap 3w units (for example) are only slightly more than an overdriven 1w.


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