Gone LED

[vira]

Lens's burned my algae. I had to take mine off. I use 3W 660nm at about 1.5" to 2" away.

Thanks.

[MorganAtlanta]

No lenses. The 120 degree spread is just right. They are so close to the screen, there's no need to focus further down.

[salty joe]

[attachment=2:1bjffs3i]scrubber_leds.jpg[/attachment:1bjffs3i]

In this picture, it looks like you are using diffusion plastic, but you only mention 1/4" acrylic. Can you tell me what you have between the LEDs and the algae?

[MorganAtlanta]

It is just 1/4" acrylic. I gets a little condensation on it sometimes inside the box.

[Floyd R Turbo]

Wow, yet another great LED build. Great job!

[Eddiee]

Why have you used 630nm led as well as 660nm? Is there a reason for this and has it gave you better results then the full 660nm builds?

[MorganAtlanta]

I used four 630s and 10 660s per side. No reason other than I was experimenting and at the time, there wasn't a consensus on what wavelengths were needed. Since then, I think there have been successful builds with just 660s. I don't have a control point, so I can't say whether having the 630s helps or hurts, but in general the design works. If I had to do it again, I don't think I'd bother though since there are successful builds with just 660s. There's no point overthinking it on the wavelength. There's probably more to be gained by figuring out the right on/off photoperiod to take advantage of the strength of the LEDs without burning the algae.

[Floyd R Turbo]

I got a tidbit of advice from someone regarding wavelength and intensity again recently, and I can't recall what else I've heard, but I believe that the 660nm is used more efficiently by the chlorophyll "A" that the 630nm is used by the "B". From the Horticulture side though, the 630s grow more watt per watt because they have much higher intensity. Again I really wish I had time to run my experiment.

The addition of a blue LED in roughly a 7:1 ratio red:blue apparently helps the roots grow better, at least according to one long-time LED scrubber user on here (Rygh IIRC) so with the 660 throw on a 425/435 violet and with the 630s a 455. Actually I think either blue would work.

[Ace25]

Floyd, can we see some PAR readings to show the difference your claiming?

I have taken PAR readings from China 640's and 660's as well as Cree 630s and OSRAM 660's. The OSRAM put out more PAR than any of the other red LEDs that I have personally tested (and probably why Ecotech picked them for their reds on their Radion light), so that goes against what your saying, that 630 is more intense. PAR=Intensity. I think the intensity of an LED depends on the LED/Mfg more than the specific wavelength.

[Floyd R Turbo]

I have no data to back that up. Sorry. That's what I remember hearing from the hydro guy I was working with to build the custom fixtures. Maybe the intensity of the 660s has been improved? It wouldn't surprise me that it has changed in the last 6 months. It seems like anymore all of the grow lights you see are 660s, so that says something...