So far, 20 days into using this LED over a 30 gallon tank I can't find anything bad about it. The setup is decribed here: http://www.aquaticplantcentral.com/f...led-light.html
Simply put - over that 30 gallon cube tank I have 2 lights. Both are running from 5PM to 11PM:
a 30W LED Flood light meant for landscaping but emitting 10,000K
a 24W 6000K Giesemann Midday bulb with its own reflector.
I did quite a bit of reading about spectrum and it does seem that the following things form the bottom line: 1. You need enough "punch".
The light can't be excellent as far as spectrum is concerned but not be powerful enough. From what I've seen with my setup the LED seems to provide the punch and the Midday bulb - the better spectrum.
- LED+T5HO are on: Pearling = 100%
- Only T5HO: Pearling = 0
- Only LED: Pearling = 75%
Did you catch the interesting point? Why isn't the pearling staying at 25% with the T5HO only? Looks like there is a beneficial interaction between the "strong arm" light and the "good spectrum" light. 2. The spectrum needs to be full.
There is a notion that the Blues are more important than the reds and any other wavelengths. ADA has apparently build their new LED light according to that view (discounting reds as both not-so-contributing to the photosynthesis and also being quickly absorbed by the water). But to use only certain wavelengths is not the natural way to go. There are some kind of interactions between the different wavelengths that make the photosynthesis both more flexible and more efficient. No wonder - this is how the sunlight is and plants have adapted to exactly that. We can't invent something that makes plants do what they can not naturally do (jump over their potential). But as usual - we can force, market, and make look cool anything we want - amazing, fine, mediocre, and even just plain bad. I am not dismissing ADA's AquaSky here, just trying to have common sense. 3. It looks like white light is not just to please the human eye. It works. Just like it did in the old days.
Look at any LED light that was specifically made for a planted tank - it has actually very little specialty LEDs (blue and red). So they provide the wavelenghts but not the punch. And that works? How is that? Blasting the plants with not-so-useful white light plus a little of the best light produces amazing results? Strange. One thing to keep in mind is that very much noone can show results with many planted tanks that show which light setup is working the best. 4. Designing a killer planted tank light is still a questionable affair.
Do your reading and you will think that unearthing exotic LEDs that emit uncommonly seen wavelenghts would make for a killer planted tank light. Well, the following is not an advertisement but I'm making a point: One company (can't post a name, thread will get deleted) offers a cool looking gadget - an online tool to design your own LED light. You select the length of the fixture and drag and drop whatever LEDs you want, where you want them. The choice of wavelengths is the best you can think of, actually beyond that. Drag, drop, pay, receive! No humans involved! Nerd heaven! BUT! Does a light like that grow better plants than a T5HO bulb you can buy and mix with other T5HO bulbs?
In all this we maybe looking at things the wrong way. Any light can grow plants because the plants adapt. This is how they survive, right. Let me tell you a dark secret - yesterday I opened a trash can that I have had in my garage for 4 months. With the lid never off that is... for 4 months. It has driftwood covered with Bolbitis. 4 months in complete darkness, 100F in summer and now 40F in winter and the Bolbitis has sprouted more than 30 new leaves. Yes, in the dark the plants use different ways to survive. No, the leaves are not looking like a million dollars. And the light was not even close to what we are discussing here at all. And I have done that cruel experiment with Anubias too - but it stayed inside a black plastic bag inside a thrash can for 9 months. And it had 5 new, pale leaves! So remember an important phrase: "Adaptable plants". Rememeber that when you think of a fancy-shmancy light to show more of the colors of your ego. Just took these pictures 5 min ago:
Actually I remembered now - when it was still hot I opened the thrash can once. In a split second the mold spores literally formed a cloud above the bin. I inhaled all of them at once and quickly closed the lid. That was the only exposure to light in 4 months. And... don't let me ever kiss you - you will get mold spores in your lungs too I guess... Joke aside note the fact that even mold won't live long where this Bolbitis managed to sprout so many new leaves. There was no sign of mold when I took these pictures 5 min ago. "Adaptable plants" indeed!
So if we focus at designing the light itself we can indeed find some setup that promotes the photosynthesys the best. And what is "best"? 5% better than the other lights? Ok, if that makes you happy so be it. This starts to look like it's not about the plants but about you. As it often is. Another facet of the hobby for people that enjoy that sort of stuff.
So back to my setup - a 30W 10000K LED + a 24W 6000K Giesemann midday bulb. Average K is right at 8000K. Hm, this number right there has lately started to come up as the best Kelvin for platned tanks. ADA knew that 10 years ago of course. So my combo works very well, right Kelvins or not, right spectrum or not, right intensity or not. I can make the plant pearl within minutes, on demand, by adding liquid fertilizers. Algae does not grow. Certain plants (swords, lotus) still manage to pearl and make leaves even though the nutrients have been depeleted to where the new leaves stay small and are very pale. So the mixed light is not causing any issues and it is driving things to run in high gear if that's the goal. Now I wonder how long this cheap LED will last. The element itself is Epiled so it should last for a long time. Will it? We will see. So far I'm getting more than I ever expected.