I was wondering if anyone with a DIY fixture has ever run it with just the optics over the blue LEDs and not the whites? I found that when I had mine above my frag tank (48x18x12) that not having optics on the whites meant I could turn up the intensity on them without bleaching or discoloring any of my acros. The fixture was hung 5" above the tank and its only a 24" fixture so I know it's technically to small for the tank. The fixture has 40 Cree LEDs and I can dial the intensity of the blues and whites to whatever I want them to be. I'm experimenting right now and hung the fixture above my 120 without any optics on it and just let it run one of its pre programmed light cycles and again all the acros look great with great polyp extension. Haven't noticed any of them losing color and turning brown yet but the tank is 24" deep. So this is why I'm wondering if I should put the 90 degree optics back on the blue LEDs only just to make them more Intense and get more penetrations I the bottom of the tank. So if anyone has tried this before or has any ideas please let me know.
I'm not running optics on any of mine. But I would tend to think that the blue leds pack more of a punch than whites in terms of energy that corals use. Its interesting that whites caused corals to bleach.
I'm frankly still a bit unclear on white LEDs anyways...as I understand it they are simply blues with a phosphorus coating making it look white. If light looks white, does that mean its white? White light technically have all the color spectrum, right?
It seems like one has to be a quantum physicists with a masters in biology to put all of this information together into something that makes sense.
Yes, true "white" light is composed of the entire light spectrum ROYGBIV. Red,orange,yellow,green,blue,indigo,and violet. That's why white LEDs are measured in Kelvins and not nanometers. The kelvin rating if a white led tells you what part of the spectrum it focuses more on but it still gives out the entire spectrum. That's why some of them give off what seems to be the dreaded yellow effect and others will almost of a hint of blue in them. Same thing as halide bulbs. Those are so successful because they create and give of true white light, unlike most white LEDs which are in fact coated with phosphorus to give the white appearance. So if I have my facts straight I think the problem of the white LEDs is that the actual temperature of the led itself will cause a shift in the spectrum it's giving off. So if you run your whites at a higher intensity, over time that led is going to hear up, hence why we mount them on heat sinks and some units have fans. And when it heats up I believe it gifts the spectrum some what and if your running optics on them then that's why sometimes you can get browning or bleaching of your corals because the spectrum shifted to probably somewhere between blue andgreen or orange on the spectrum which that chart that Jim posted clearly showed that chloroform a And b can't absorb energy from the light in those spectrums. So you are pretty much hitting your corals with intense beams of light in the wrong spectrum that it needs and I have found that will cause the browning of acros and occasional bleaching as well. But again I'm in no way a physicist so I'm just going off research I've done and people that I've talked to.
LED Colors?
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