Btw what model crees are you using? xp, xr-e, etc.
and would you be so kind as to post a front pic of the leds to see how they are spaced out?
have you checked temp on heat sink being enclosed like that? and what heat sink did you use?
your light cycle is 18 on and 6 off right? didnt see it posted.
hope im not pestering ya too much but you beat me to a build like i had planned so i just want to pick your brain and copy what your doing.
thanks for sharing
No optics on my LEDs, they are already close enough to the screen, any optics would make it way to strong and focused. Right now I get almost perfect spread, just the outer corners are slightly dimmer than the rest of the screen. Optics should only be used when the LEDs are at least 12" away on a tank, even then with 60s you still get some spotlighting/color bars from the optics. I have played with all of them on both XR-Es and XP-Gs to see how optics help LEDs. They do increase PAR A LOT (too much in most circumstances) but the trade off is very focused light and not much blending of colors.
I have been thinking more and more about taking off a neutral white and replacing it with a royal blue, maybe just do it on one side so I can see if there is a difference between growth on each side.
The spectrometer I have at work. I have borrowed it a few times but it is easier for me to bring bulbs I want testing into work so that is what I have been doing with LEDs and CFLs. I brought it home when testing different T5s and MHs in my canopy to try and determine replacement age of bulbs based on spectral shift instead of PAR (intensity) or time. I have a 48 LED light over my 75G and a 24 LED light over my 29G that I made. The 48 uses cool blues, royal blues, cyan, cool white, neutral white, and warm whites, my 29G is just royal blue and cool whites.
The LEDs are 3 per 10" piece of 2"x1" C-Channel aluminum, one dead center, the others are 3" out from center. Right now I am using XR-E LEDs because it was what I had left over from my original 48 LED build, when XP-G neutral/warm whites were not out yet. I do like the size/lense on the XR-Es vs the tiny XP-Gs though, I think it helps with the spread. I think the XP-Gs are around 120degree and XR-Es are 100degree, so slightly more focused, just not as energy efficient. The heat, yes, is a concern. I am making lids for the tops of the boxes right now and using 2 1.5" fans on each side with holes drilled in order to circulate air in the box. Without fans it gets up to 120 degrees on the heatsink, with fans they stay almost room temperature, so fans are required and I use fans on all my builds.
Yes, 18 on / 6 off.. just started though with a new screen, so it will take a little while to fill in. I remember my first one taking about a month to get a good base down and 2 months to really start working good.
Don't worry, your not pestering me at all.. I like to help.
48 on 75g. sounds nice some builds i see use over twice that. do you have a build thread on it and/or the 29?
and for your heatsink. is it a finned design or a solid plate or angle shape? thickness?
sry. just reread thread. on my phone so couldnt before i posted. c-channel. 1 x 2. i assume its standard channel right? not heavyweight
Ya, standard aluminum C-Channel, not heavy duty. On my other LED lights I used finned heatsinks. Here is my build thread for my LED light.
http://www.aquariacentral.com/forums/sh ... -going-LED
Just to give you an idea of the difference between 48 LEDs and 375w of 10K MH light
This is an XM 10K 250w MH bulb, run on a PFO M80 magnetic ballast, so it overdrives the bulb to 375w, This is the PAR output at 12" from the light.
Now compared to 48 LEDs, same distance from light
Conclusion, 48 LEDs is about 2x stronger than a 400w 10K MH bulb.
thanks. eleven pages. guess i got some reading to do now at work lol
two quick questions
is spectrum same from the mh to led and therefore the reason for wide array of leds in 48 build?
have you grown frags in 29 and 75 from same colonies? and if so. did you notice a difference in growth or color that you could attribute to having only two types of leds on 29 versus the 6 on the 75 or was that just for aesthetics?
ok two and a half lol
The 48 LED build was my first.. and I was trying to cover the most spectrum possible. Looking at them under a spectrometer, there was a large gap between royal blues and Cool whites between the 470-520nm wavelengths, upper blues and Cyan were missing in the spectrum. Also the entire spectrum under 450nm was non-existent, so I have 4 420nm T5HO Actinics on my 75G to cover the low end of the spectrum. This is one area I really think LEDs need a new breakthough in, blues. The whites are great, put out more than enough PAR and have a great spectrum, now we need a blue LED that isn't monochromatic, more like a blue that covers 420nm-500nm range, that would help out a ton. The rest of the spectrum coming from the LEDs, especially cool whites, are a much better spectrum overall compared to most MH bulbs, which are actually very rigid/lots of peaks under a spectrometer. White LEDs are a much smoother curve than a MH. Only colored leds are pretty much mono-chromatic, so royal blues put put a very narrow spectrum, and now the thinking is it caused HEV, meaning too much photosynthetic light at the chlorophyll B absorption point, leading to over saturation and doing more harm than good to corals. Problem is, you need a lot of blues to balance out the whites if your like me and like the 20k look. If you add more royal blues to counter the whites, you end up putting way too much of that specific wavelength onto your corals, so I chose to go with cool blues and cyans instead of doubling up on royal blues.
Honestly... after all the designing of my 48LED light, I can honestly say that my 24 LED light is actually growing SPS corals better. Not entirely sure why that is but it is a puzzle I plan on figuring out.
Regarding blue versus red needs:
I ran an experiment on my old turf scrubber, where I replaced one of my Red/Blue/Red LED clusters with
one of the Cool white + royal blue from my display tank cluster.
The RB/CW definitely did not grow as well as the one with the R/R/B.
See middle of page 23 on my first LED thread.
viewtopic.php?f=3&t=435&start=220
Now that does not say blue is not important, and it might have been a bit overloaded with blue, but it is a useful data point.
---
Second thing : Go look on various sites where they grow algae for biofuel with LEDs.
Almost all of them use Red+Red+Blue.
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That said, I believe it will grow OK under whites. Simply because you do have decent PAR numbers.
But fun to optimize.
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PS: I am jealous of access to that spectrum analyzer.
I appreciate your input rygh and I do agree with you. The 2 photosynthetic peaks are 453nm and 660nm, blue and red, so it makes sense why those 2 colors would be chosen to grow algae with. I just didn't have any reds on hand and since I love to tinker and test all things lighting related (I am a reef geek but an UBER lighting geek) so I figured I would try out what I had to see how well they do. Neutral whites have a good amount of blues in them and warm whites have some reds (although they do not reach up to 660nm, which I can see being a potential problem). So I agree with you 100% that my LED choices are not going to be the most ideal choices for maximum growth, but I wanted a starting point. I don't want to have happen what happened when I put my LED light on my 75G.. nuked the crap out of my SPS corals at first. Even matching PAR for PAR between LEDs and the MH it replaced, the LEDs put out way more 453nm than the MH did and that nuked my corals. PAR is only one piece of a puzzle, knowing the true spectrum of the light used I think is more important than PAR. PAR only equals intensity of the light within the 400-700nm range... so in theory you can have 2000 PAR coming out of all GREEN LEDs, and not be able to grow a thing with them even though you have the PAR output that matches the sun.
One thing about BioAlgae for fuels it is a freshwater algae they use from everything I have read, so it has slightly different requirements in lighting vs marine algae in my opinion. Different topic to get into but that is one area I can talk for days about because I do think BioAlgae is going to save the planet vs things like corn, palm, etc. That one topic gets me more excited than any other topic right now in my life but this is not really the thread for that. I think even my co-workers are sick of hearing about BioAlgae as an oil replacement because I talk about it constantly at work.
The question I have now though is "what is the correct spectrum for maximum growth of marine algae". I do believe the ideal spectrum for marine algae is going to be different than FW algae and really different than terrestrial plants due to the living environment that marine algae comes from. Anything more than a couple inches under saltwater gets a large majority of the red spectrum filtered out (90% at 12") so if algae grows in the ocean at depths deeper than 12", chances are it is not receiving much red light, unlike terrestrial plants. Looking at my tank now, I can say by the daily handfuls of algae I am pulling out lately, that LEDs will grow algae very well, much better than my T5s and MH ever did, unfortunately that wasn't what I wanted to grow, I was trying to grow corals. LOL. I do believe over the eons things like marine algae will adapt to their environment in order to utilize the light spectrum it receives as efficient as possible. So I think marine algae will not utilize the reds as much as a lot of people think it will. It will still use it, I just don't think the standard photosynthesis chart you see that pertains terrestrial plants are an accurate representation of what marine algae or corals will utilize most efficiently.
Bottom line is, my current Neutral/Warm white LEDs put out a better spectrum and the same PAR as a 42w 2700k CFL bulb and I get better coverage so in theory my current LEDs should blow away any CFL ATS out there.. but I do think there is plenty of room for improvement on my end with different LED choices. I just wanted to start "safe" and progress upwards, instead of going the other way like I did on my display LED light, start at the top, nuke the corals, and work backwards to get back to acceptable lighting. Last thing I wanted was to prove Santa Monica right in that LEDs just make burn circles on screens and can't grow algae, which is entirely possible if the LEDs are not setup correctly/lenses used to close to screen.
Yes, I know what you mean by wanting to just get it done.
My latest system is a bit sub-optimal as well, because of the LEDs I had around. May improve it later.
I should have my big new diplay tank LEDs done in a week or so, and after that might
have some time for more tinkering.
Yep, agree with you on the whole PAR thing.
BTW: Make sure to consider the LedEngin deep reds. They are one of the very few that really
reach up into the correct upper-red spectrum. Interestingly, they are not a red LED.
They are like whites, in that they use a different base LED, and then phosphors to output.
And as such, seem to have a wider spectrum as well.
(As well as my cheesy diffraction grating spectrometer shows)
You have a VERY interesting point about freshwater versus saltwater algae.
I never thought about that. Need to look into it.
Although I would be a bit surprised if fresh/salt hair algae is very different, as opposed
to coraline, kelp, and things that are more specifically marine.
As far as blowing away T5/MH. Well, hope so.
I actually think the "perfect" LED will simply equal the "perfect" CFL/T5 as far as growth.
Simple because I don't think lighting will be the limiting factor, once done right.
But it will certainly blow it away from a power + long term cost standpoint.
And hey, I would be quite happy if it ends up better.
Funny, I was reading your DT LED build thread, and it looks
like you noticed the LedEngine parts already.
Never mind.
Off topic tidbit: I used both Rebel and Cree royal blues, to help spread
out the blue spike. They are fairly different in spectrum, especially when
bin sorted.
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