What's the general consensus for the best red/blue LED ratio? I often see a range from 4:1 to 8:1. The 7:1 ratio was the best ratio done by NASA apparently. Not sure how accurately this relates to GHA specifically. Has anybody noticed better growth with different ratios?
I'm not sure there is a consensus. My take on it is that you can not really have "too little" blue, but you can have too much. Also unclear is what that 7:1 represents. Is it intensity? Radiometric flux? Simple number of light sources? It's probably the flux. So if you have an array with 20 reds, throw in 2 blues and you'll be good. But on a quantity of LEDs level, I wouldn't use much more than 1 blue per 6 reds, you want primarily red. I use 2 half-current blues and 6 reds on my boards, more of a matter of convenience and simplicity in laying out the arrangements. 2 half-current blues probably put out more than one full current blue, but it seems to still work OK. Adding any more blue I think would not help, probably would over-light the screen. I have one L4 that is starting to look over-lit in the middle actually, it's not on a heavily fed tank and might be running too long of a photoperiod, so I might try bypassing the blues on one side completely to see what happens. Good one for the benchmark testing... @acorral
Is there some reason to use 450 blue over 420 violet? If I remember right Chlorophyll A uses about 420 violet and 660 deep red and B uses about 450 royal blue and 630 orangeish red. So I never understood why 450 and 660 are often used together... Something I am missing?
I think that historically a reliable 420 was not really available, at least not a cheap one. That has been the main reason. You are correct though, A is 420/660 and B is 450/630. From my reading and research, A is the primary and B is more of a sunrise/sunset bandwidth. B bandwidths (from the sun) penetrate the atmosphere during these times, while A does not. Nor does it on cloudy days (I think). Steve's carried a violet that i was eyeing for a while then he pulled it. Seems it was de-laminating, they didn't last long. He now carries a hyper-violet that he says is much better. http://shop.stevesleds.com/Hyper-Violet-V30-Vio30.htm This one has a big dome on it to focus the beam to 60 degrees. You can take a thin razor and slice it off halfway up and you get a nice square-ish wide angle distribution. I am planning to test these shortly, as long as work and family life don't kill me like last year...
I got a pack of 8 1 watt 420nm i got on ebay for $3 on an uncontested bid. I should hook them up and see how they look. That panel I got in the other thread claims to be 420nm, and looks that way... I dont have a way to measure it though. I think they are getting to be more common.
I use 420-ish on my 40b scrubber and it grows the best algae. I need to change my other three to include 420 but, aahh, yes, call it busy and to lazy when I am not. However I did just finish a dual LED fixture for my 75G that included 420, looks nice.
I got 8 interesting little violet LEDs on ebay for a $3 bid. They were listed as 1w 420s but were labeled as 410-430nm on the back of the LEDs themselves when I got them. I probably should have put them in my scrubber but I made a pico display light out of them instead. They are being driven at 600mA. For reference the LEDs in the center are 2700k Luxeon warm whites from Stevesled. These litle violets are amazingly bright looking, so I assume they must be on the higher end of violet. Since this light is mostly ~420/660 I am curious to see how the critters do.
Nice. When I was e-mailing with Steve about using the hyper-violets on algae scrubbers instead of the blues, he said that they have had a tough time finding violets that didn't delaminate over a relatively short period of time. This is why they dropped the old one that they used to carry and not carry the SemiLED version - he says that one is built a lot better. So that might be why you got these cheap, I guess time will tell but for $3? pfffft sure!!
Yea, my original violets I got from groupbuyled turned brown and delaminated after a while.... but honestly it wasnt a big deal. I just took the covers off and they were fine, just no optics. They would probably be better for scrubbers like that anyway. The semileds "hyperviolet 2.0?" (They are basically 2 smaller diodes together and were rated by steeve for 1000mA) ones I got from steeve like a year ago still look fine, and they have been running at 700mA.
I have to be careful with my 420nm leds on my display light (it has 20,000k and 450nm as well), if I burn it to hot it outcompetes my scrubber 420/450/660nm combinations.
Same boat here with my 125 reef. I have a mix of Cree royal blues, and a mix of 2700k warm whites and 6500k neutral whites. With my 420s and daylight from a near window if I am not careful I loose the scrubber/display balance. I was doing really well for a while leaving my L2 scrubber on 24/7 and running a TON of water through it (~600GPH), but I had to be careful about how I cleaned the screen, if I scraped off everything it would take forever to regrow and the display would start to out compete it, but if I left a bit of fuzz in a week it was PACKED full. lately though it hasnt been growing so great, might be the sun angle against my window on my front glass, or the fact that I have ONLY been feeding a small amount of Nori to my sailfin tang each day. Either way it means I gotta get off my backside and scrub my display glass. Time to check the scrubber too.... I think it has been over 2 weeks since I cleaned it out....
This is my sump light, I just tossed all the LEDs I had on some heatsinks and have been running them for a couple years. They have been running 24/7 for the last 4 months or so. The center LEDs are 420s I bought from groupbuyled when I made my first display light, which was maybe 2010? I dont remember for sure. The build on optics browned and melted ages ago, but they still work fine. So I would not worry about melting/browning optics as long as you could pop them off without ruining the LED.
