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DIY led lighting - have I got it right before purchasing

7K views 21 replies 7 participants last post by  csf 
#1 ·
hi all

great forum. I think i've interpreted everything right so
this post is more for clarification before purchase then anything.

i'm a freshy with planted tanks and native australian fish, I've decided to start updating my fluros to LEDs.
my trial tank is 1200x450x700 (47x17x27) - 378L (108g)

here is what I'm planning;

heatsink- makers 36in - great product, well done
LEDs- Cree 14x 3up(2rb/1nw) 40 deg optics
Cree 8x 3up(3cw) 40 deg optics
exotic 3x hv 60 deg optics
exotic 3x dr 60 deg optics
? 3x cb 120 deg optics
power supply - 12v 6a - I'll source local so I don't need an adaptor
- query - as long as I cover the required current with
1a buffer. I don't need to worry about VAC
drivers- inventronics 1x 25w/700ma
inventronics 1x 40w/450ma
inventronics 5x 40w/700ma
controller - dim4 sunrise/sunset - query- is there a limit to the number of
drivers I can connect per channel
relays - 2x relays & sockets to run fans

now for the led setup

ch1- 2x (40w/700ma---4x 3up(2rb/1nw))
ch2- 40w/450ma---3x hv, 3x dr, 2x 3 up(2rb/1nw)
ch3- 3x (40w/700ma--- 4x 3up(3cw)
ch4- 25w/700ma---2x cb

i've chosen the channels to give me control over whites, blue/whites, colours &
moonlights separately.
from my calculations this should be much more than needed for plant growth, but I'd rather have more and be able to dim ( & leave the opportunity open to become a reefy with the addition of a few LEDs and some salt)

please let me know if I've done anything stupid
I'd appreciate any comments or thoughts
cheers
az
 
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#2 ·
You sure you got enough LED lighting to grow plants with that? From what I can tell you got the equivalent of 18 cw/nw Cree LEDs total in your lighting (not sure what the 3x hv and 3x dr are).

Also, have you checked the geometry on your light array? How high are you planning to mount the lighting? 40 degree optics makes for a pretty narrow beam.
 
#3 ·
thanks for your input

to clarify
14 x 3up(2rb/1nw) = 28rb & 14nw LEDs
8 x 3up(3cw) = 24cw LEDs
total of 28 royal blue, 14 neutral white & 24 cool white.
I'm hoping this blend will give me a nice full spectrum about 10000-14000Ks (not that kelvins mean anything to plant growth) I shouldn't need any more blue as I don't have coral.

I've added hyper violet (hv) k deep red (dr) to try and mimic PAR wavelength peaks

my tank is 32in high so even if i have the lights directly on the tank top it would be 2.5 feet from the substrate. my light will be suspended about 1 foot from the top of the tank. the 40 deg optics will give good penetration getting usable light to the bottom.
 
#4 ·
You might actually have too much blue light in that tank XD. What overall color temp are you looking for? I know color temp doesn't really matter for plant growth, but it does matter for our own aesthetics =]

From personal experience I've seen 5 cw to 1 blue ratios work out very well. The website buildmyled.com also uses this ratio for their showtank lights (though I've never actually purchased their lights before). You might want to buy some extra LEDs and experiment with the color mix when you hvae them on hand.

If you buy LEDs from china via ebay you can get 10/50/100 pack sets of LEDs for real cheap. Not as high quality as CREEs but totally worth the value IMO if you make your fixture flexible. My brother uses them extensively and has no complaints. I've read though that cheaper LEDs have issues with their color temps deterioriating over time whereas the CREEs have a guarantee that their light intensity and color temp will remain at a certain % of specifications after a period of time. The LEDs online are 1/8 of the cost ($0.80 vs $4.00) so I can't really complain (though you have to wait 2 to 4 weeks for them sometimes).
 
#5 ·
cheers mate.

I'll do a little digging on the ratios.
I've written down in my notes that 1rb:1cw = 10000-12000k ( I haven't noted where I got that info from).
the addition of the extra cool whites (5000-8300k) should soften the effect. can anyone confirm if I've got this right?

I'll have a look at the cheap LEDs. from my understanding the crees put out more light using less energy ( thus meaning less driving power for each string or more LEDs)
as well as what you mentioned with the accurate wavelength peaks. if the led peaks at the wrong wavelength then it potentially could be useless to plants become purely mood lighting ( eg red (670nm) and far red (730nm which is outside PAR).
 
#7 ·
the app looks useful. cheers mate.
unfortunately i can't drop the LEDs onto the strip using my I-pad.
this means I'll have to venture upstairs to the civilised part of the house :)
i'm worried that it doesn't give a kelvin rating after adding blues.
while not being a factor in plant growth directly, kelvins is an important factor to penetration.
6500k at the surface means far less at the substrate.
for mid and cover plants apparently 8000k-10000k is needed.
most data out there is for a 24 in tank. all I can find is that if you have a deeper tank have more kelvins.
reefers need 14000k+ due to the fact that they need to replicate light conditions that are natural at many meters deep for coral growth.
 
#9 ·
thanks for doing that steve

there seems to be a lot of yellow and green in the spectrum (wasted energy?)

i'm still concerned with the kelvins ( in regards to penetration)

"It is also noteworthy that many "terrestrial plant lights" as well as many aquarium plant lights (often are lower in kelvin temperature) have more "red nanometer spikes" than higher kelvin 6500k, 10,000k & higher lamps.
The problem with these lights is that while all plants utilizing photosynthesis require the same essential ABCs of PAR (see the PAR section), the facts of light energy penetrating water requires higher kelvin (6500k +) be added to provide maximum PUR (see Useful light energy/PUR section). Aquatic Plants and corals have adapted/evolved to the natural light energy at certain depth of water and the misguided attempt to adapt these terrestrial plant lights is not going to be 100% effective as a light with more water penetrating blue & slightly lower red nm energy."
aquarium lighting by carl strohmeyer

I,m starting to think about adding some reds in strategic locations about the substrate
 
#12 ·
that's some real food for thought ced
thanks

I was just reading the red spectrum causing algae. also plants (and coral) have adapted to their natural depth which means that too much red can be detrimental.

i understand what you're saying about the visual aspect of the yellows and greens.
it still amazes me that the colour things appear is the colour they're not.

i think i'll stay with my reef capable amount of blues but play with my wiring so that blues, whites, pur colours and aesthetic colours can be controlled and dimmed separately. thus i can have whatever temp/spectrum i need.

what i love about the diy led approach is that if i think i'm short of red or whatever i can just add a couple of LEDs and problem solved.

i haven't ordered yet but i shouldn't be far off. just finalizing some details.

let us know how your build goes. are you using dimmers?
 
#16 ·
Red to Far Red Ratio

Nick,
what are your thoughts on the red to near red ratio?

i think I read somewhere in can be used as a way to measure PUR.

more importantly, i've just been doing some reading on phytochromes and was interested in this.

"Finally, phytochrome allows plants to detect the spectral quality of light, a form of color vision, by measuring the ratio of Pr to Pfr. When a plant is grown under direct sun, the amounts of red and far-red light are approximately equal, and the ratio of Pr to Pfr in the plant is about 1:1. Should the plant become shaded by another plant, the Pr/Pfr ratio changes dramatically to 5:1 or greater. This is because the shading plant's chlorophyll absorbs much of the red light needed to produce Pfr and absorbs almost none of the far-red light used to produce Pr. For a shade-intolerant plant, this change in Pr/Pfr ratio induces the plant to grow taller, allowing it to grow above the canopy."
McGraw-Hill Encyclopedia of Science and Technology

mmmm
does this mean with 2%far red we should only have equal 660nm.
if we increase both to the 20-40% range would that be detrimental.
maybe a balance. down to 7-15% for both.

what does every one think??
I'd be keen to hear your thoughts Nick.
 
#18 ·
Nick,
what are your thoughts on the red to near red ratio?

i think I read somewhere in can be used as a way to measure PUR.

more importantly, i've just been doing some reading on phytochromes and was interested in this.

"Finally, phytochrome allows plants to detect the spectral quality of light, a form of color vision, by measuring the ratio of Pr to Pfr. When a plant is grown under direct sun, the amounts of red and far-red light are approximately equal, and the ratio of Pr to Pfr in the plant is about 1:1. Should the plant become shaded by another plant, the Pr/Pfr ratio changes dramatically to 5:1 or greater. This is because the shading plant's chlorophyll absorbs much of the red light needed to produce Pfr and absorbs almost none of the far-red light used to produce Pr. For a shade-intolerant plant, this change in Pr/Pfr ratio induces the plant to grow taller, allowing it to grow above the canopy."
McGraw-Hill Encyclopedia of Science and Technology

mmmm
does this mean with 2%far red we should only have equal 660nm.
if we increase both to the 20-40% range would that be detrimental.
maybe a balance. down to 7-15% for both.

what does every one think??
I'd be keen to hear your thoughts Nick.
Hi Az. Since plants are not able to choose their home, they have become extremely good at adapting to their immediate environment in order to increase their chances of survival. One of the best ways they do this is by using their Phytochrome proteins to sense their environment. This category of photobiology is called photomorphogensis. This is completely different than photosynthesis, but it is a very important part of the plant’s lifecycle. With photosynthesis, we are focused on using the right type and right amount of light to grow the plant. With photomorphogenesis, we are focused on using specific light signals (photo) to impact the plants development (morphology). The Phytochrome gets a lot of attention, but we should also be aware of the Cryptochromes and Phototropins, as they both play an important part in plant development.

Back to your original question, I don’t pay too much attention to the Red to Far Red (R:FR) ratio for most lighting applications, since most people are focused on Photosynthesis (i.e. bigger plants). If you are trying to induce a Phytochrome-related response (i.e. induced flowering, delayed flowering, taller plants, etc.), then you need to pay attention to the R:FR ratio. Per my earlier post, green and far red (especially far red) are transmitted through the plant canopy at a higher rate than blue and red. Over time, plants have figured out that a high level of far red light probably means they are being shaded by taller plants. Since they need light for photosynthesis, the plants realize they need to shift their energies into growing taller to get above the other plants. If they don’t, they probably won’t survive very long. Once above the canopy, the R:FR ratio changes, and the Phytochromes tell the plant to stop growing tall/spindly, and to put their energies back to growing more leaves/branches to catch more light for photosynthesis. This is called the Shade Avoidance Response, and it is a really interesting facet of photobiology. As mentioned, you can also use 660nm and 730nm to induce or suppress flowering in short day plants (SDP) and long day plants (LDP). I have worked on large commercial photomorphogenic lighting applications, and it is really amazing stuff.



Hope that helps :icon_bigg



Nick
 
#20 ·
nice info
it would be fascinating to study.
slightly off topic. there are some amazing living sculptures using plants that are trained.
people are even weaving saplings to make walls and houses as they grow to trees.
nature is awesome.
 
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