Ace's ATS v2.0 - LEDs

[kerry]

Never had a detachment issue yet, I just see spots that the algae come off easier then other areas so I hit them with the saw again to be sure I do not have issues. I also hit the red algae spots with the saw every now and then to keep it knocked down.

[Ace25]

Hello Ace,
Thanks for all the detail you have provided on this project, it is very interesting and helpful.
Has your opinion changed about this?
These 6 LEDs on each side of a 13x10 screen should create a desirable growth rate for a scrubber?

I am planning to make a new ATS and would like to try using LEDs.

Thanks
Kevin

Yes, today I still think those LEDs will provide excellent growth on an ATS. Do I think it is the most ideal lighting for algae? No. Do I think it is better than white lights (CFL or LED), BIG YES. We are all hoping Floyd will be able to really give us the answer on what combinations of LEDs is the most ideal, but regardless of what he learns, white light is not going to be part of the answer. The only real question now is how many reds/blues, what wavelengths, and what ratios to put them in. Today I am thinking it may end up being something like 4x 630nm/6x 660nm/1x 425nm/1x455nm but my "guesses" seem to change monthly so don't take that as the final answer.

Until we figure it all out all I can say with absolute certainty (since I am running it) is that 6x 660nm 3w LEDs per side will give very good growth on a 10"x13" screen, much better than a 42w CFL bulb.

For the other questions, watts per sq in is really not something I would even attempt to figure out with LEDs. I know it would be nice to have an easy answer but with LEDs that is just not possible. LEDs are so different in so many ways you just can't use watts as a measurement tool. Things like wavelength and amperage draw are 2 of the biggest factors and reasons why using watts won't work. Even Lumens doesn't work because we are dealing with monochromatic light sources. The lumens coming off a Red or Blue LED will be a small fraction of what comes off a white LED, but the wavelength coming off the Red LEDs is 100% usable light, not so on white LEDs where a lot of the spectrum is just wasted light. This goes back to the "intensity vs spectrum" debate. I can put 1000 lumens of white light over an ATS screen and still not get 1/2 the growth as 100 lumens of Red light because with the white light 950 of the lumens are outside of the spectrum that is ideal for growing algae and the 5% that is within the spectrum is mostly in the blue region, not the red region.

Same thing with PAR, a Cree XP-G Cool white running at 1000mA will put out 200 PAR 2" under the LED by itself, where as a Red LED only puts out about 40 PAR, but that entire 40 PAR is usable light by algae where as out of the 200 PAR in the cool white LED, only about 50 PAR is usable for algae, and out of the 50 PAR, 45 of that PAR is in the blue spectrum, none in the upper red spectrum. Only Warm Whites have some noticeable red spectrum, but still do not reach up into the 660nm area.

As far as screen cleaning/roughing, I have never re-roughed up my screens. They always hold algae and once the algae is established as long as you don't go overboard cleaning the screen, you will always have a base of algae stuck to the screen, which to me tells me I have no reason to want to re-rough up the screen. It is like saying "well, the tree is rooted and growing good, but the ground around it is too hard so let me dig up all the roots in order to soften the ground for the roots".. well.. destroying the roots is worse for the tree than giving it softer ground, which is how I think of the screen/algae. Once it is rooted to the screen, it is there to stay unless you do something harsh to remove it. Only when the screen gets too thin and starts breaking do I think about replacing it, which is usually about 1 year, but that is when it first starts to get thin, I bet I could easily go 18 months before it really needs replacing but since they are so cheap (screens) I just replace them yearly.

[kotlec]

Until we figure it all out all I can say with absolute certainty (since I am running it) is that 6x 660nm 3w LEDs per side will give very good growth on a 10"x13" screen, much better than a 42w CFL bulb.

Using 3W leds at 700mA makes them actually closer to 2W. Thats why I asked about total wat. Just to be sure. I also use 660nm LEDs.

So we get 12W of 660ers for 130 sq/inch - or 1W per roughly 10 sq/inch. Right ?
Now I have 8w spread over 3" x 4 " screen. Omg its 8w per 12 sq inch when I actually can go with 1,5 wat. Auch.

[kerry]

I have fast growth with the 660nm LED's. I fire them with 660mA's and have them about an inch away from the screen. Its still brown growth but its getting the nutrients to zero-ish.

[Ace25]

One other reason "watts" isn't the best measurement is due to distance the LEDs are from the target. 6 LEDs (and your correct, I am running mine at 2.1w) may be perfect on my setup because it is 2" from the screen, but put those same 6 LEDs 4" from the screen, and you may only get 1/2 the growth, so in that case you may need 12 LEDs if you have to place them further from the screen. This is why I find it so hard to give anyone a "one size fits all answer" when people ask me about LEDs. There are too many variables you have to consider before you can give a # to the amount of LEDs one would require.

Your math sounds right to me though basing it on my working setup, 12.6w of 660nm LEDs for 130sq/in IF the LEDs are 2" from the screen.

[kotlec]

My LEDs are actually 1" from screen. Ouch.

[wgood33]

Ace, you wrote: "We are all hoping Floyd will be able to really give us the answer on what combinations of LEDs is the most ideal, but regardless of what he learns, white light is not going to be part of the answer. "
Can you post a link for me to this string? I too will convert to LED on my ATS, so this info will be great. Sorry, just starting to follow along in this forum. Thanks, Bill

[Ace25]

He has posted about his experiment in several threads, but hasn't made one specifically for the light test. I am sure when he gets to that point he will create a thread for it.

http://www.reefcentral.com/forums/showt ... 045&page=4
http://www.reefcentral.com/forums/showt ... 0&page=108

Off topic, here is a display light I made for Johnarky's 60G cube tank. 14 Cree Royal blues, 12 Cree Cool whites, and 4 moonlights + a BoostLED Typhoon PWM controller.

[rossco838]

How do you like the reef angel controller?...looking into buying myself an early xmas present

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[rygh]

How do you like the reef angel controller?...looking into buying myself an early xmas present

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FWIW, I have used one for about a year.
I love how it is fully programmable.
Also very cheap.
Lots of add ons.
Great support and forum.
Downside : Well, its built a bit cheap.