For a really useful DIY, how about someone build a test of ten different led's next to each other, all the same except for spectrum, and see which one grows the most. Then use the most-growing one in your scrubber.
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For a really useful DIY, how about someone build a test of ten different led's next to each other, all the same except for spectrum, and see which one grows the most. Then use the most-growing one in your scrubber.
Yep, thought about that.
After all, I currently have CFL and LED next to each other as of last night, so stay tuned for results there.
The problem is, it is not that simple.
- It is not exactly a cheap thing to do.
- LEDs of different spectrums have different luminance.
- You also need to test combinations of wavelengths, not just one.
- No single vendor has all the wavelengths to test.
But I may think about it some more.
One advantage to my setup is that it is 35" long, and only 6.5" wide, so pretty easy to test different things on different sections.
And if I mount each LED to an individual heat sink and mount, it might be easy to move things around.
I really want to try the "simple" version of basic deep-red + blue first.Quote:
Originally Posted by inkidu
And deep-red I think more of as an optimization, not truly different from regular red. So no real need for other reds.
The lumens on royal blue really drop off, so not very efficient.
lm is what the eye perceives. Radiometric power (mW) is something different. From what I have read so far they are hard to compare.
Thanks for the reply.
The cool whites I use do work. I do believe you could consider them to some extent to be yellowish-white.
Let me try to be as clear as possible by what I see is the problem by oversimplify what is very complex.
If you put 8000 lumens,of white light, one inch away from a screen and there are nutrients available, you will grow algae.
That is simple enough.
If you use colored led lighting, especially when you consider the very narrow frequency of very expensive
color leds, and efficiency is of importance than there is a need to be as accurate as possible with the selection of the leds.
This in my mind is where there is some grey area. I do not believe when you consider the very specialized nature of
color leds and when you considering all the variables( sw or fw, flow rate, vertical or horizontal, nature of your base water, the
variability between leds) that a choice of what type, color, and ratio can be easily made by the most common graphs.
There is also the ? of the how the screen will mature though different types of algae.
Lumen with leds cost a lot of money. If you wanted to be as efficient as possible than color leds seem like what you would want to use.
I am using a power head that is pushing 475 gph at 0ft.
I have a couple small whisper air pumps. I can't be using many watts. If I was not heating my tank to 85 degrees
This setup would be next to nothing to run. I am only pulling 1 amp out of the wall to power my lights.
Hope this helps
Santa Monica,
Maybe an assortment of very specific/narrow color temp (ANSI) leds that luxeon sells. I realize you do not favor a horizontal scrubber but that
setup might be useful for a test i.e. line them up along the length.
Thanks for any help.
Yes if you are just test spot-growth from each led, then it does not matter the layout, so long as the flow is the same for all.
To clarify the whole lumen/mW notion:
Lumens = mW / 683 * "luminous efficiency of humans".
The luminous efficiency peaks at 555 nm (=1), and falls off to 0.0001 at 380nm / 750nm
You need to ignore the "luminous efficiency of humans" in these calculations, since of course, this is algae we are talking about.
So royal-blue, even ignoring the efficiency, still drops off badly.
Agree: The whole point of the careful spectral research here is to optimize power efficiency.
- And at $0.25/KWH these days for my bills, that quickly turns into real money.
That is another of the key reasons I will run at 700mA. I could go to 1400mA, but I do not get nearly a 2X increase in lumens.
I pay for that up front, by having to buy more LEDs, but I save in the long run.
I think indeed that a working version will need many low-power emitters. A continuous even spread of light is critical; even on my 100, if you look at the ends, growth goes from green to brown in just a half inch, because of the drop in light at the end of the T5.
Well, LEDs have a surprisingly good distribution pattern.
Cree has about a 20% difference across 80 degrees.
LedEngin is a bit worse, with a 20% difference across 60 degrees.
Thus an LED that is put 4 inches from the screen can quite nicely cover a circle 6.5" in diameter.
So I you distribute them 6.5" apart, you actually get double coverage in between.
From my first test setup, I did not see any difference in growth across the screen.
On my Rev2 build, I added a micro-diamond lighting diffusion panel for the top, instead of simple clear acrylic.
It definitely gets the light bouncing around in there. But I do lose some light.
Plus, everything is painted white. And flat white paint actually bounces light better than most reflectors. It just bounces it in a random direction.
Reminder from earlier in the thread: I measured the light distribution from a CFL flood lamp, it it was not particularly good either.
So certainly an issue that cannot be ignored. But with a little planning, quite solvable.
And I think the low efficiency and DIY pain of the small emitters make them a non-starter.
How about this to diffuse the led light.
http://www.guardian.com/en/na/PatternData.pdf
I mention it because I want to mix the different colors as
much as possible while putting them as close as I can to my screen. Still thinking about going vertical.
Good transmission with decent diffusion?
The cost might be high but, if I can put a system together that runs efficiently and has less/easier maintainess,
I will live with the upfront cost.
Any opinions? (I want to stay away from acrylic for light transmission)
Glass is easier to clean and want scratch as much.
Also looking at the Whiteoptics/White97 for refection and dur-iflex as possible cheaper alternative
to the glass for diffusion as well.
Big ? is the cost.
Any help would be appreciated.
That diffusion plating looks interesting. Did you find a place that sells just a few square feet to a hobbyist?
I tried the small micro-diamond diffusion grating.
Basically, the cheap stuff with small diamond shaped bumps that you get in the lighting department of home depot.
I am not very happy with it.
It spreads the light around great. Works well in that aspect.
But it reflects light back like crazy. Pretty bad for transmission.
So I am rethinking that.
Not sure why you don't like acrylic.
Generally transmits 90% for a 1/8 piece. Same as 3mm glass.
And for a simple ATS shield, you can easily use 1/16 or even less. (Home depot picture frame acrylic. Super cheap)
There is a big loss in the UV range, but who cares.
My latest plan is just to move the LEDs back a bit from the screen, and go back to simple very thin acrylic.
And make sure everything, especially sides, is painted white inside.
Interesting, another new problem I have is condensation. Those water droplets get pretty big on a semi-horizontal system.
And without the heat from a normal light, don't really evaporate.
It was not really an issue on my old vertical. Another one of those tradeoffs to remember.
Not sure how to solve that. I really want a sealed system.