I know penny pinching is often a time honored tradition on many freshwater forums. But this is a reefkeeping site - an expensive hobby in its cheapest forms.
So rather than that cost being prohibitive, I suspect a large number of people here would jump at the chance to spend $100 once on some lights that you wouldn't need to replace for upwards of 15 years. IMO - Beats the heck out of the time and waste generated by swapping CFL's every three month. It certainly sounds better to me, particularly when considering the environmental issues with disposing of CFL lights (in particular).
That is true. However, there is an interesting item to note here. I work on a few airport runway re-lighting projects each year. These are the small municipal airports, and they have to follow FAA regs. Some big airports are using LED, but the smaller ones are adamently refusing to use them. Why? Because runway lights need to be pure white, and taxiway lights need to be blue. Since the white LEDs are actually blue with phosphors added to shift it, there is evidence that the white light actually shifts to blue over time. Again, another unknown. While the shift to blue wouldn't be bad, because the WW LEDs are lacking a bit in the blue range, it might actually be a shift away from red on that end, which would be very detrimental. This problem may have already been solved though, the next time I bug the Cree guy I'll ask him.
The other thing to remember is that the driver board and/or power supply will likely fail before the L70 date of the LEDs is reached (that's what the 50,000 or 100,000 hour lifetime is based on - hours to 70% of lumen output). At that point, you'll have better, cheaper, more efficient LEDs out there and it won't be worth replacing the board or PS, you'll just get the newest fixture. So 15 years is probably not a reality.
First, while LEDs for scrubbers is still an experiment in progress, with no clear proof or defined architecture for being the light that drives an ATS that replaces all other filtration, there's plenty of evidence out there to indicate that it can be quite sufficient for supplemental filtration. If you plan on continuing to run a skimmer, and are just looking for an ATS to replace that Chaeto ball tumbling in your refugium, this could be just the ticket.
Yes, definitely good for supplemental filtration. I don't think that primary filtration is far behind though.
Second, it is important to note that while the typical cool white plus royal blue combination is definitely not ideal for growing algae, it is safe to assume that it does grow it. If it didn't, with all the people out there running nothing but CW and RB over their tanks, we'd be hearing about "LED DT lighting as the key to eliminating algae". But we're not. So it's safe to assume that algae - being the highly adaptive and opportunistic organism that it is - will try hard to use what ever light you give it.
Yes, I thought about that too. Algae has always been around and it adapts well. But you also cannot fool mother nature. While it will grow in essentially any light, what we want is it to grow at it's maximum to minimize power useage and maximize effectiveness. At least, that's what I want!!!
But the lighting you explained above would certainly appear to be much better.
It's just a guess at this point. But it seems to make sense. I wish I had a pile of $$ laying around and a bunch of free time...
It looks to me that UV is not even desirable, so is this relavent?
It's just an unknown. There might actually be some component of UV light, however infintesimal, that contributes to plant growth in some way, shape, or form. Fluorescent tubes give off UV light, which is why under the meat counter the bulbs have a plastic shield around them (1-to protect meat from broken lamps 2-to keep meat from turning gray in a few hours). But, that being said, acrylic and glass are excellent UV blockers, but there is some component that gets through. While it may not directly influence growth, there could be some component to natural sunlight / mercury based light that LEDs are missing. I'm just pointing out that it is missing in LEDs lighting, which makes LED a completely different animal from other standard types of lighting. Will it make a difference, and is it the missing piece of the puzzle? Probably not, be wo knows for sure.
One thing is for sure, don't go buying UV LEDs. UV light can cause damage to us humans.
Algae is a plant. Does algae need a different PAR range than most other plants? I'm not trying to bust your chops or anything like that, but some of this does not make sense to me. And I certainly appreciate all the help you have given to people working with algae filters.
PAR is a measurement of quantum light. That is, is it a measure of the amount of raditaion per unit area and unit time. PAR meters eliminate the human factor, but if you want to measure the level of radiation at a specific wavelength, you're looking at a super-expensive meter. The basic PAR meters out there just measure the total PAR. So you could have tons of blue and no red and your PAR would look just fine, but you would be missing 1/2 of the spectrum.
But yes, algae is a plant, the difference is that it's not a flowering plant, and is likes certain conditions. What I find interesting is that one article that says natural sunlight is 80,000 lux and algae growth is best between 2,500 and 10,000 lux, and growth hinders at 15,000 lux. You don't see plants shriveling away because of too much sunlight though. So is there a difference in the requirements of plants versus algae or any aquatic macro for that matter?
Not many people out there are even looking into making lights to grow algae, that's the problem. There's this big flaming ball in the sky that works just fine. Plus, the algae needs a resting period, so why supplement it with additional light when it doesn't want it. Like I said, you can't fool mother nature.
I agree with all of you, great points here and there, some i think may be opinionated/assumptions, but great none the less.
As far as what Floyd said about 100 bucks in LEDs, I donno, i think i might have to disagree with that. You mentioned that 350mA could be too bright, so if you ramped them up to 900mA, it should be way way way too bright. Mix that in with a diffuser to spread out the light, i think that you should be fine. So lets say that you have a 12x12 screen, (going to do some assuming here as i dont have a test subject), and that you hve 4 quad LEDs. That means that each LED powered at 900mA only has to cover 6sq", which isnt all that bad, a little thin on the outside, but should be ok depending on the distance from the screen. And with how intense they are, you souldnt put them all that close i wouldnt think, compared to CFL's.
Is that you crawling around in my brain?
2. (just thought of it this morning.) Do it how TV's do it. Edge lit LCD's. This is done for other projects like some DIY Microsoft Surface tables. The back side of your acrylic will have a mirror reflective surface, the front will be diffused, and the LED's inject the light from the sides. The light mixes from being bounced around inside the acrylic and is then ejected out through the diffused layer. Theres more to it but thats a general break down.
Interesting idea. Making it work in the ATS application would be the real challenge. Good way to diffuse light though.
