1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Purple LED's

Discussion in 'General Discussion' started by atoll, Mar 23, 2017.

Welcome to Algae Scrubbing Join our community today
  1. atoll

    atoll Member

    Some people are recommending purple LED's as opposed to blue LED's in their ATS lights, any thoughts? .
     
  2. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    That's what I've been using for years. 100%, yes. 410-425nm hyper-Violet SemiLED from Steve's LEDs is what I use. They are reliable. Off-brand as getting better but SemiLED makes the best. They make a 60 & 90 degree version, I use the 90
     
  3. TbyZ

    TbyZ Member

    What advantage do you get from the purple as opposed to using just 660nm ?
     
  4. atoll

    atoll Member

    What combination of reds to purple are you using is it 3 to 1? an Reds at 660nm?
     
  5. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    6 reds (660) : 2 violets, violets at 50% of the reds
     
  6. TbyZ

    TbyZ Member

    What advantage do you get from the purple as opposed to using just 660nm ?
     
  7. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    It has to do with the chlorophyll peaks, 660 and ~415 go together for chlorophyll A, 630 & 455 go together for chlorophyll B. So 660/415 is a better match than 660/455. you see 660/455 stock fixtures because 45 is cheap and reliable, but 455 is overly intense, 415 is a better match.

    The violet/blue is essentially supplementary to the process IMO, it tends to make the algae a bit more resilient (for lack of a better term)
     
    TbyZ likes this.
  8. trivodi

    trivodi Member

    47
    5
    USA
    the purple grow algae much better in my opinion an dthe alge is more stringy sort of, its not so fine like hair but more stiff
     
  9. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Yes - the blues or violets seem to "enhance" growth, or make the growth "fuller"
     
  10. herring_fish

    herring_fish New Member

    2
    0
    Why don’t you have a ratio of 6 reds (660) : 1 violet at 100%?

    Is that done for the purpose of coverage or is there a benefit from having two at 50%?
     
  11. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    With the arrangement that I use, which is 6 Red LEDs in 2 rows of 3 (all 2" on center) placing a single violet in the center results in 3 LEDs at 1" on center right across the middle.

    On Rev 1, this is the arrangement I used, except with a Royal Blue, and they were all at full power. This generally created a bald spot in the center, and over time, also caused degredation of the screen in that same location (there could have been other factors)

    In Rev 2, I switched to 2x 1/2 power blues. This was better.

    On my personal Rev 1, I modded that to have 2 full-power violets (string of 8 per side) and that worked OK, but I still got a bit of differential growth in the center. Not much though.

    I never bothered trying a single violet in the middle of the array, because I wanted to avoid the possibility of the bald spot coming back. So the TL;DR answer is "coverage"

    However, my driver board has SMD pots for each channel. So you can adjust each group of reds and blues - the default is Red channels 1 & 2 at 100% of the external pot, and violets at 50% of the external pot.
     
  12. TbyZ

    TbyZ Member

    Hi Bud; I saw a post of yours on reef central where you stated your minimum coverage was One LED (660nm 3W @ 700mA) on each side for every 8 sq in of screen." I use a minimum ratio of 0.67 LEDs per 4 sq in of screen, where as your ratio works out to be 0.5 LEDs per 4 sq in of screen.

    Your minimum ratio would equate to 3 LEDs on a 6" x 4" in screen. It seems a bit lean to me, so I'm wondering if you have used that minimum ratio on any scrubber you've built, & if so, how was the growth?

    cheers
     
  13. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    It's mainly a ballpark estimate based in the intensity, what you really need to do is make the light array match the screen dims you choose for even coverage, so for a 4x6 screen that would probably more properly be 4 per side instead of 3 just for even coverage. It's not a set-in-stone formula that you must follow by any means, it just helps you get an idea of the range of quantity of LEDs that you want to shoot for.

    The 1-per-4-sq-in is the ratio I use. But when you get to a really large screen, like 12x12, now you're at 144/4=36 LEDs, which might cause some people to choke on the cost, so if you scale back to 24 or something, that's still in the range (18-36 per side). That's the idea.

    That being said, my L16 which is 12x16 uses 48 reds per side (and 16 violets), so that still follows the 1-per-4 ratio. I've found it to be very effective over a wide range of capacity, especially when you can dim them - you have the intensity to push it to the limit, or you can back it down and still have even coverage, whereas if you have less LEDs, you can get spotty growth if you are forced to us on/off as your means of controlling the growth
     

Share This Page