Gomer Posted January 24, 2008 Share Posted January 24, 2008 LEDs are getting a lot of attention these days. Their packaging is reasonable to deal with. Their efficiency is getting quite good. Their price has gone down a lot making them on the verge of mainstream economical. They have been shown to grow coral fairly well. What is not to like? we..., LEDs are quasi discrete sources. We mix and match wavelength proportions and use a single phosphor to get the shade of blue/purple/white that we like. Lets look at the typical light that we LED users give to our corals. . You'll notice a few things. 1) strong dominating peak at ~450 2) med-strong broad peak at ~575 3) dip at 500 4) barely any light below 450 5) barely any light below 675 When we want to add more of a blue or purple look, we add more LEDS (normally called blue or royal blue) that are either ~450 or ~460nm which just makes the strong peak even stronger and nothing else. You don't add anything new, you just emphasize. Why is this important? Coral color. We are in the hobby not just to grow coral well (which I think LEDs can do just fine) but also for pretty colors. If you have perfectly healthy corals, your color comes from 2 things 1) reflections 2) fluorescence We know reflections well. Plants are green because the chlorophyll absorb red and blue but reflect green. We know fluorescence. Ever put a black light on a "hippy poster"? Or just run actinic in your tank? The crazy glow/colors most people love is more from fluorescence then reflections in my experience. Fluorescence works by absorbing a wavelength and re-emitting it as a color more red (longer wavelength) color. Absorb purple, emit blue. Absorb green, emit yellow. etc etc. You can even have multi process and large band fluorescence where you absorb purple and emit something far out as green. Now back to the LED spectra. Look at the deficiencies. I think part of the color issue I have experienced (others please comment on this) is due to this. We are missing out in the 500 region a reasonable bit (yellowish green), the far red a fair bit and the deep blue almost entirely (not UV. UV doesn't really start till below 400 and 375 and above is pretty safe. How much color are we loosing out on because of this? I think a lot. Link to comment
Hans Dorn Posted January 24, 2008 Share Posted January 24, 2008 Hi Gomer, I've also noticed the lack of green with LED lighting. I'm running 12 white and 12 royal blue LEDs at 1W, over a 6.3gal (24 litres) I'm seeing some nice flourescence from the royal blues, but I don't know how this compares to MH/actinics. My tank is in a pretty sorry state ATM (BGA killed virtually everything in it), but it will hopefully recover with time. I have hardly any coral in it right now, so I can't comment much on any effects of LED lighting wrt. life stock. Regards Hans Link to comment
coolwaters Posted January 24, 2008 Share Posted January 24, 2008 its true that LEDs lack a lot of Green. thats y u have to add that in. i heard Solaris is adding like 3 Green every 25 LEDs. something like that. guess you people dont care about the red.... unlike MH or T5s LEDs has a stay cold...or at least cool. MH reaches max output at X amount of heat. but LEDs the colder it is the more efficients it is. (until about -40.C i think) at 15.C its 110%. according to the chart. but keeping it that cold is going to make up a lot of power so theres no point. i thought people didnt care about red light? Link to comment
coolwaters Posted January 24, 2008 Share Posted January 24, 2008 DO the PITFALL OF MH!!! Link to comment
Gomer Posted January 24, 2008 Author Share Posted January 24, 2008 BAM!!!!! You just fell into a pit. Both of you. White LEDs do NOT lack green. Asside from the big blue spike at 450-460, what is the other hump? It has a maxima around 550-575nm GREEN!!!! White LEDS have a TON of green. What are LEDs lacking? Cyan (~500nm), red (600-700) and the deep purple (<450). Cyan is a blueish green and our tanks really don;t lack that. Red? YES we do lack rred with LEDs. WE don't get that much there directly so we just get red from the smallish amount of direct red plus fluorescing of "orange" and higher wavelengths. So why are we lacking green? I am willing to bet that most of the green and brilliant colors we see in our tanks are NOT direct reflections (ie what we are used to in our everyday life of seeing color). What we are lacking is Fluorescence. The GLOWING color you get when you shine one color, it gets absorbed, and re-emitted at a more red-shifted wavelength (if you put in 500nm wavelenth, the fluorescence color will be > 500nm). So what are we lacking? The deep purple! That range <450nm. When we crank the royal blues, we add a ton of 450, but the tails (remember, LEDs emit a "bellcurve" of light) are what are giving most of the fluorescence. Who wants to bet $ or corals etc, that when you take add in these 390 or 405nm UV LEDs that you get all sorts more color in your tank? You'll get those greens and other goodies that we are lacking. ...Now, if only they had high powered 650nm, 420nm and 400nm LEDs. Link to comment
strangelove Posted January 24, 2008 Share Posted January 24, 2008 its true that LEDs lack a lot of Green. thats y u have to add that in. i heard Solaris is adding like 3 Green every 25 LEDs. something like that.i thought people didnt care about red light? Yep there are green LEDs in a solaris. I'd be intersted to hear how mixing LEDs spectrums work. I think I read somewhere that Japanese reefers are using red LEDs for their tanks. Link to comment
coolwaters Posted January 24, 2008 Share Posted January 24, 2008 lol i should have took a closer look at the chart (i blame size of the chart its too dam small...now im stuck in a pit...)they got the 400-420s already. i dont think anyone would get the red...the UV LED is rated at 385-410nmsorry 627 nm is the highest i found... Yep there are green LEDs in a solaris.I'd be intersted to hear how mixing LEDs spectrums work. I think I read somewhere that Japanese reefers are using red LEDs for their tanks.dont they use optical lenses to mix the lights?i was using bare LEDs and didnt like the color mixing so figure i'd get the light diffusers. Link to comment
Hans Dorn Posted January 24, 2008 Share Posted January 24, 2008 Heh - that's what you get for trusting your eyes instead of checking your spectra To be more precise - my macro algae LOOKED more green with PC lighting If adding green or cyan LEDs will do more for increasing your viewing pleasure would have to be tested. Regards Hans Link to comment
Gomer Posted January 24, 2008 Author Share Posted January 24, 2008 Heh - that's what you get for trusting your eyes instead of checking your spectra To be more precise - my macro algae LOOKED more green with PC lighting If adding green or cyan LEDs will do more for increasing your viewing pleasure would have to be tested. Regards Hans It LOOKS more green cause the LED has more yellow to dominate the green. Your eyes/brain blend colors and gives you the result. Link to comment
Hans Dorn Posted January 24, 2008 Share Posted January 24, 2008 Yep. Color vision is a tricky business. We don't really have red and green color sensors in our retina. The "red" ones have max sensitivity at about 560nm - a greenish yellow. The "green" ones are at 530nm - a bluish green. Our brain has to subtract these two from each other to detect red or green. Regards Hans The blue receptors are at 420nm BTW - we gots UV vision if we go by LED marketing Link to comment
Gomer Posted January 24, 2008 Author Share Posted January 24, 2008 I am generating ~210nm UV in the lab...think they will let me fluoresce ...or burn the coral at home? LOL Link to comment
121a Posted January 24, 2008 Share Posted January 24, 2008 sorry, but LEDs i know are the future but, we can also mix them with CCFLs. That would give us a red for only about $15. Or you could just add red LEDs. They also come in a wide varity of colors, green, blue, UV, purple... they are mostly used for computers but i have seen them used as dimmable moonlights. I think my post was kinda random, but i was going to experiment with LEDs too, but changed my mind. I still know a few things though and I'm interested in knowing more. Link to comment
coolwaters Posted January 24, 2008 Share Posted January 24, 2008 thats going to fry everything...and cause cancer... i wouldnt go below 380nm.... anyone willing to put red light in there tank? i got a 1w red on stand by.... Link to comment
Hans Dorn Posted January 24, 2008 Share Posted January 24, 2008 I just checked my pH after 12 hours of lighting, and it's at 8.7, with a freshly calibrated meter. Yikes! Does this mean I already throw more light at my tank than it can handle? I'll try cutting down lighting hours. Regards Hans Link to comment
Gomer Posted January 24, 2008 Author Share Posted January 24, 2008 I'm actually running my BC 12 with 6 cree Qbin at 700mA. one 50/50 and one 03 actinic. The LEDs DOMINATE the "white light" from the PC. I am tempted to replace the 50/50 with actinic so I have LED + Actinic only.What I'd want to do is whitebalance a camera, then use a series of descrete LEDs over a tank and look at what colors actually cause what fluorescence. You may find that a red LED adds a lot of deep red fluorescence with minor red reflection..who knows till you try! Link to comment
coolwaters Posted January 24, 2008 Share Posted January 24, 2008 thats cool comer. btw lighting effects the pH? have u tried using a liquid pH tester just incase? Link to comment
Hans Dorn Posted January 24, 2008 Share Posted January 24, 2008 Yep, I guess some red LEDs would make a difference. My tank looks brightly blue with the royal blues only, and a greenish yellow with the white Crees. Some red LEDs should give more contrast to the green algae. I have a couple of them flying around, will check this out over the weekend. Regards Hans. P.S: I can see some faint dark red flourescence coming from the macro algae when the royal blues are on Link to comment
Hans Dorn Posted January 24, 2008 Share Posted January 24, 2008 thats cool comer. btw lighting effects the pH? have u tried using a liquid pH tester just incase? Yep. It's about the same ballpark (somewhere around 8.6) My alk dropped from 12 to 9 DKH within a day, too. I feel like my tank is haunted Regards Hans Link to comment
Hans Dorn Posted January 24, 2008 Share Posted January 24, 2008 I am generating ~210nm UV in the lab...think they will let me fluoresce ...or burn the coral at home? LOL Is that from a LED What Vf do you get there, should be around 7-8V I guess. Link to comment
coolwaters Posted January 25, 2008 Share Posted January 25, 2008 lol would they even let u tank it home? that stuff is a radiation hazard... Link to comment
Gomer Posted January 25, 2008 Author Share Posted January 25, 2008 Perhaps I should say that it is from a laser No, I can't take it home. I couldn't even fit the whole setup in a pickup truck LOL. Link to comment
Hans Dorn Posted January 25, 2008 Share Posted January 25, 2008 BTW, do you know where I can find some LED spectra in ASCII format? I'd like to play around with these in Excel and I'd rather not try digitizing pixel coordinates from data sheets Regards Hans Link to comment
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