Tunable 5 channel LED light for scrubber

[Creekview]

I'm a tinkerer, and have built several LED projects. My latest is a scrubber light for my horizontal flow scrubber that allows me to dial in each wavelength known to promote chlorophyll production across the range of marine algae. I did a lot of reading and research, and ran across a commercial system built by Phillips Lighting that uses 3 tunable bands of LED light to grow algae for food and biofuel production. My reading led me to decide on 445 & 460nm (blues), 630 & 660nm (reds) and 6500k white LEDs. eBay vendors supplied the 3w LEDs, power resistors, and PWM dimmers. Got 10 each of the LEDs, the resistors, and 5 dimmers. Ordered 120 degree lenses for the LEDs. Total outlay, less than $40. I use 1"x2" 1/8" wall rectangular aluminum tubing for all my heatsinks. 20' of the aluminum was $60. I have built several fixtures out of the tubing. Works great even running 20 10w LEDs on a 4' light. Power is a surplus PC power supply using the 12v output. Timing is by an Oktimer THC15a programmable industrial controller. Pics below:


Command and control

Light laying across control board for photos


445nm



460nm



6500k



630nm



660nm



All on



Inside the scrubber

[SantaMonica]

Will be a nice experiment. If you back the lights away, they might mix together better.

[Creekview]

I have a piece of prismatic plastic I'm gonna put in between and raise them an inch or two. Should even out the coverage. Before that, I'm going to put in new screens and see what kind of algae grows under each LED. You can see where the previous 10w light coverage ended. Bare screen.