Anyone Thinking of Dumping LEDS and going back to Halides

[shred5]

[PEDANT}
No they are not. They are still missing big chunks of spectrum. The only lighting source that I am aware of that is truely full spectrum (think the sun) is the Iwasaki 6500k.

Whites are broad spectrum. What most people seem to prefer for their reef tanks is missing almost all of the spectrum above 500nm save a big spike at 550nm and smaller spikes in the 600nm to 700nm range.

Full spectrum in the reefing world is a misnomer.
[/PEDANT]

While true, we already know that led dont have a UV spectrum, white led is the widest spectrum they offer.

But the point is most people with led have more issues than they should because they Like the way their corals fluoresce under royal blue and run too much blue. Eventually these corals loose colors because they are used to a wider spectrum.. Now again it depends where these corals come from but usually when we talk color we are talking SPS and most SPS come from shallower water and are used to a wider spectrum.

 

[JPMagyar]

Probably so I'm an led guy at the moment, but threads like this have me awfully curious. Especially never having tried MH.

The Oregon Tort is notoriously slow growing, but here's 3 months of growth under metal halide . . .



January

March

 

[markalot]

I still don't get the spectrum side of this argument. Newer LED combinations can provide a reasonably wide spectrum light that while still not perfect is a lot closer than it used to be.

I will beat the dead horse to restate that the main issue I see with LED is the lack of proper spread/reflection that results when too few fixtures are used. For LED to work correctly, IMO, the tank needs to be literally covered in LEDs.

Remove the coverage problem, bath the corals in light from all sides with no hot spots, and then we can start to talk about results with the different LED combinations.

Unfortunately I don't think manufacturers are going to lower prices and recommend more fixtures any time soon. Until that happens a couple of LED pucks blasting point source light from above will never look good to me, regardless of the quality of light it produces.

 

[mhucasey]

I still don't get the spectrum side of this argument. Newer LED combinations can provide a reasonably wide spectrum light that while still not perfect is a lot closer than it used to be.

I will beat the dead horse to restate that the main issue I see with LED is the lack of proper spread/reflection that results when too few fixtures are used. For LED to work correctly, IMO, the tank needs to be literally covered in LEDs.

Remove the coverage problem, bath the corals in light from all sides with no hot spots, and then we can start to talk about results with the different LED combinations.

Unfortunately I don't think manufacturers are going to lower prices and recommend more fixtures any time soon. Until that happens a couple of LED pucks blasting point source light from above will never look good to me, regardless of the quality of light it produces.

I agree 100%

 

[Fredfish]

While true, we already know that led dont have a UV spectrum, white led is the widest spectrum they offer.

...and broader spectrum, in some respects than all the successful MH and T5 lights, but still not full spectrum.

We've moved beyond full spectrum as a requirement for coral growth and colour. The spectral plots of popular reefing lights look nothing like what you find on a real reef at any depth that you find corals.

I agree completely with markalot. Coverage and the cost to get good coverage on an LED only tank are the challenges that remain.

MH and T5 may still be the gold standard, but the gap between them an LED has narrowed to the point that we will continue to see LED TOTM tanks on a regular bases. To me, more choice is always a good thing.

 

[maidia]

The Oregon Tort is notoriously slow growing, but here's 3 months of growth under metal halide . . .



January

March

Very nice, I want a frag

 

[lpsouth1978]

...I agree completely with markalot. Coverage and the cost to get good coverage on an LED only tank are the challenges that remain.

MH and T5 may still be the gold standard, but the gap between them an LED has narrowed to the point that we will continue to see LED TOTM tanks on a regular bases. To me, more choice is always a good thing.

I completely agree with these statements. I have used LED on several tanks, all DIY set ups. The first was not very successful, but worked. It was all Blues and Whites, Cree 3W diodes.

The second was VERY successful, great color and growth. It was a 34 gallon tank with 72 3W Chinese LED's in 6 colors.

I am now building a fixture for a new 300g build. it will have 456 3W LED's in 7 colors. We could have used fewer LED's, but wanted to be sure we had great coverage. In all, the light build will cost me nearly $4000. As stated before, cost is an issue, but if they work it will be worth the cost in the long run.

 

[JPMagyar]

I still don't get the spectrum side of this argument. Newer LED combinations can provide a reasonably wide spectrum light that while still not perfect is a lot closer than it used to be.

I will beat the dead horse to restate that the main issue I see with LED is the lack of proper spread/reflection that results when too few fixtures are used. For LED to work correctly, IMO, the tank needs to be literally covered in LEDs.

Remove the coverage problem, bath the corals in light from all sides with no hot spots, and then we can start to talk about results with the different LED combinations.

Unfortunately I don't think manufacturers are going to lower prices and recommend more fixtures any time soon. Until that happens a couple of LED pucks blasting point source light from above will never look good to me, regardless of the quality of light it produces.

Full Spectrum is a term used by manufacturers to describe the color rendition of their LEDs. It is not in fact accurate from a physics stand point. The graphs they present to "demonstrate" the spectrum are generated using instruments that are not digital in nature and use smoothing algorithms to create the graphs. There are a very few materials that produce LED light and the wavelengths they create are limited. There is no known way to get a "spectrum" out of an LED. Manufacturers have gotten quite good at mixing materials at a nano level so as to have red, white, and blue LEDs mixed on a microscopic level thus creating the appearance of a "cool white" LED, but that "cool white" LED has big gaps in wavelengths that will only appear if you use very expensive equipment that can count photons of individual wavelengths.

This does not mean a "cool white" LED can't grow coral. It just means it doesn't have the same spectrum as metal halide or fluorescent, and the difference is observable in how certain corals color and grow, and that doesn't mean all corals or even most corals; it just means some corals. That is what I believe I have seen and that is what I believe Krzysztof noticed.

LED technology has not changed. There is a finite number of material combinations that create a finite number of colors. The mixing of different color LEDs is virtually limitless, but it doesn't alter the nature of LED light. Contrary to the graphs produced by low cost spectrum analysis instruments, LEDs produce narrow bandwidths of light. This fact remains unaltered. YES, LED light can be used effectively to grow MOST corals. LED lights can NOT grow coral as well as MH or T5 and the tanks of the best reefs show this on a daily basis. It's a hobby and you can use the light you like, but you can not change the physics of LED light.

 

[JPMagyar]

This is a quote from more than 500 posts back and not the first of it's kind. Not sure how many times I need to explain this on this thread. YES, we all know LEDs can get the job done. They are not and can not ever be the same as MH or T5 because of how the physics of light production in an LED works . . . .

Again, you did NOT read my post.


1) LEDs can NOT have the same "spectrum" as light produced from metal halide; it is a physical impossibility.




LEDs produce light using P/N junctions. P/N junctions are the same technology used in making microchips and create mini-transistors that science has been making smaller and smaller by the year. The material used to make these junctions determines the wavelength of light produced by an LED. Let me say that another way. The wavelength of light produced by an LED is determined by the material used in making the LED. Scientists have found several suitable materials which can create several different LED "colors" and they found that mixing these LEDs can fool the human eye into "seeing" even more colors. What LEDs do NOT do is produce a broad spectrum of light as is created by a metal halide bulb or a fluorescent bulb. LED light is different; it can NOT have a broad spectrum. Period, dot, end of story.

There are numerous studies that have examined how symbiodinium grow under artificial light created by metal halide and even in depth research into the absorption curve and reflectivity of broad spectrum light. In that research scientists found that symbiodinium response seemed to differ with different wavelengths, but no research I have seen has shown whether light from sources that have very narrow wavelengths alters the response of symbiodinium as compared to broad spectrum light. There are more scientific reasons why LED light is different but I'm not going to waste time typing what I already typed above. Prove to me that you are listening at all and go find my previous posts on LED light and then show me the scientific papers that have studied these issues with regard to symbiodinium, and while you're at it why not go find the papers that DO exist on symbiodinium and artificial light.



If you like LEDs that is awesome. This is a hobby and you should use the light you enjoy most. This thread is a place where some very experienced reefers, myself included, are sharing their experience with LEDs and saying that something is different about how SPS grow under LEDs especially given the fact that LEDs are so varied in their application. If you disagree with that FACT then I'm afraid we simply have to agree to disagree.

How 'bout some pictures of your reef while we're at it. Or perhaps some macros of the awesome colors you are getting.

Here are some of mine. . .

 

[mhucasey]

LED technology has not changed. There is a finite number of material combinations that create a finite number of colors. The mixing of different color LEDs is virtually limitless, but it doesn't alter the nature of LED light. Contrary to the graphs produced by low cost spectrum analysis instruments, LEDs produce narrow bandwidths of light. This fact remains unaltered. YES, LED light can be used effectively to grow MOST corals. LED lights can NOT grow coral as well as MH or T5 and the tanks of the best reefs show this on a daily basis. It's a hobby and you can use the light you like, but you can not change the physics of LED light.

There was some talk of a new type of LED under development that would produce UV light then would be coated in the same phosphors as a Fluorescent tube, ideally producing light in the same way as fluorescents. That would be the best way to change the physics of LED. Im guessing its an expensive proposition and/or lowers the lifespan of the diode to do it that way.

 

[JPMagyar]

There was some talk of a new type of LED under development that would produce UV light then would be coated in the same phosphors as a Fluorescent tube, ideally producing light in the same way as fluorescents. That would be the best way to change the physics of LED. Im guessing its an expensive proposition and/or lowers the lifespan of the diode to do it that way.

Yes, but the key issue with that technology is that it is really the same as T5. The difference is how the phosphors are excited. If it catches on it will be a more efficient T5 not a true LED. LED stands for Light Emitting Diode.

diode
[ ˈdīˌōd ]
NOUN electronics

a semiconductor device with two terminals, typically allowing the flow of current in one direction only.

 

[mhucasey]

The Light Emitting Diode creates the Raw UV light, its not done with an electrical arc in gas like a tube.
I looked it up, from Wikipedia:

White LEDs can also be made by coating near-ultraviolet (NUV) LEDs with a mixture of high-efficiency europium-based phosphors that emit red and blue, plus copper and aluminium-doped zinc sulfide (ZnS:Cu, Al) that emits green. This is a method analogous to the way fluorescent lamps work. This method is less efficient than blue LEDs with YAG:Ce phosphor, as the Stokes shift is larger, so more energy is converted to heat, but yields light with better spectral characteristics, which render color better. Due to the higher radiative output of the ultraviolet LEDs than of the blue ones, both methods offer comparable brightness. A concern is that UV light may leak from a malfunctioning light source and cause harm to human eyes or skin.

If they make those and can reproduce the T5 color spectrums, I'd be very interested...

 

[markalot]

Joe,

I think that's hobby science. Once light is produced it's light. If the resulting spectrum doesn't match the Radium it won't look as good as the Radium. If the light is not blended as well as the radium then it won't match the radium. If the light does not cover the tank as well as a radium matched with a quality reflector then it won't match the the radium with a quality reflector. If anything about the produced light regardless of the source is different from the Radium then it won't match the Radium. Those are the limits of the facts.

I also don't buy your spectrum argument. A high rez spectrum plot of an MH or T5 shows it has numerous spikes and is hardly smooth at all. It IS different, it might be better, but there may be another combination that is different but also good. We don't know because there are no LED fixtures that can blend the light properly yet, so even if the resulting spectrum looks good the corals are under a disco ball with any fixture except possibly the Kessils, but the Kessils are spotlights.

Finally, since you quoted me, I don't use LED, I use T5 as my primary lighting with some LED for shimmer. I don't like the look of LED alone even if they can grow corals because of the reasons I stated. The picture in my avatar is a coral grown under Maxspect Razors. THe top looked great, the rest of the coral was suffering. Under T5 it is more healthy and the colors are richer.

Because I think this is more than obvious I am forced to assume you didn't actually read any of my posts. You seem too quick to post pictures of your tank and then tell us, or me, that the argument is over. There is no argument that your tank, and most tanks, look fantastic under Radiums.

IMO

 

[maidia]

Joe,

I think that's hobby science. Once light is produced it's light. If the resulting spectrum doesn't match the Radium it won't look as good as the Radium. If the light is not blended as well as the radium then it won't match the radium. If the light does not cover the tank as well as a radium matched with a quality reflector then it won't match the the radium with a quality reflector. If anything about the produced light regardless of the source is different from the Radium then it won't match the Radium. Those are the limits of the facts.

I also don't buy your spectrum argument. A high rez spectrum plot of an MH or T5 shows it has numerous spikes and is hardly smooth at all. It IS different, it might be better, but there may be another combination that is different but also good. We don't know because there are no LED fixtures that can blend the light properly yet, so even if the resulting spectrum looks good the corals are under a disco ball with any fixture except possibly the Kessils, but the Kessils are spotlights.

Finally, since you quoted me, I don't use LED, I use T5 as my primary lighting with some LED for shimmer. I don't like the look of LED alone even if they can grow corals because of the reasons I stated. The picture in my avatar is a coral grown under Maxspect Razors. THe top looked great, the rest of the coral was suffering. Under T5 it is more healthy and the colors are richer.

Because I think this is more than obvious I am forced to assume you didn't actually read any of my posts. You seem to quick to post pictures of your tank and then tell us, or me, that the argument is over. There is no argument that your tank, and most tanks, look fantastic under Radiums.

IMO

+1...SPS base or under always suffer under Leds.. I hope all my SPS look better under my new light..Time will tell.

 

[markalot]

While on the subject I want to talk about my first encounter with a Radium, which happened just this year.

One LFS near me has a big 250 cubish tank (not exactly sure of the measurements) with two Radiums (electronic ballast) and lumenbright reflectors. I brought my PAR meter to take some readings in exchange for a free frag. 750 under water line, 550 just below the level of that anemone, 250 down on the sandbed.

It's beautiful, drop dead gorgeous, and anything they put in it thrives. Just like Joe says. They also are very haphazard with dosing so KH is all over the place and yet it doesn't seem to matter, just as Joe says. There is something magical about that bulb, or MH in general, so I'm not doubting some of the MH evangelists for a second, but I won't agree that the magic can't be duplicated with LED, it just hasn't been done yet.

I purposely took pictures of this tank and my tank with my crappy phone camera using fixed white balance so I could compare my T5 coral+ heavy lighting with the Radium. It's not a valid comparison because what we see is hardly close to what the bulb is actually producing, but it made me feel a little better.

I'd also like to add some pictures of my best acro under Razors and now under T5.

LED
top

front

T5+LED

top

front

I try and avoid the LED won't grow coral argument because I agree light is light, but the Razor has that smoothed spectrum that would appear to come somewhat close to a good Halide bulb, yet the results telling. This is where I would argue it's more of a blending problem than a spectrum problem, but of course I don't know. It might also be because I had then running too bright due to the lack of that green peak that allows both T5 and Halide to look brighter to our eyes. The thing is, anything they put under the Radiums colored right up, no bleaching. My PAR under LEDs on that coral was 320 - 350 and under T5 it's 450. Again, I think the blending is the main issue, but it's a wild guess. Obviously the coral from the front looks horrible under LED, the coverage issue, and that picture above is what drove me to buy a T5 fixture the day after I took it.

 

[shermanator]

There is no known way to get a "spectrum" out of an LED. Manufacturers have gotten quite good at mixing materials at a nano level so as to have red, white, and blue LEDs mixed on a microscopic level thus creating the appearance of a "cool white" LED, but that "cool white" LED has big gaps in wavelengths that will only appear if you use very expensive equipment that can count photons of individual wavelengths.

What do you consider as "very expensive equipment"? I've seen spectra of LEDs (e.g., PC amber) on a $20k integrating sphere spectrophotometer and what I have seen with my own eyes doesn't agree with your statements. One of my colleagues in the physics department here studies novel phosphor coatings for LEDs and we've talked LEDs quite a bit.

I'd like to hear some specifics (your studies with specific pieces of equipment) and/or publications you can provide to back up your claims.

For the record, my tank is T5/LED (soon switching to MH/T5 Cebu Sun) and doesn't hold a candle to yours. I'm not pro-LED, but I'm also not following your arguments.

 

[oreo57]

If they make those and can reproduce the T5 color spectrums, I'd be very interested...

They already make these.. except mimicking T5's is NOT the goal.
Oh and the largest size (short of multi-chips) is 1/2W..
http://www.yujiintl.com/high-cri-led-lighting

high CRI violet based LED

Fluorescent.

Originally Posted by JPMagyar View Post
There is no known way to get a "spectrum" out of an LED. Manufacturers have gotten quite good at mixing materials at a nano level so as to have red, white, and blue LEDs mixed on a microscopic level thus creating the appearance of a "cool white" LED, but that "cool white" LED has big gaps in wavelengths that will only appear if you use very expensive equipment that can count photons of individual wavelengths.

that is just wrong...

White LED's are nothing but phosphor doped blue led's........and this is cheap.

Just for fun, violet based phosphor doped LED CRI index:

 

[Cyberdude]

Anyone Thinking of Dumping LEDS and going back to Halides

A photon is a photon regardless of its source. I 100% agree. Wavelengths will vary and it just happens the MH works. There was a post in this thread that I think nails it on the head. What's the one thing led show case tanks have in common. They are bathed in LEDs. End to end coverage no spot lights or single led pucks (unless for a nano tank) seem to the the job.

I have a 36" wide that was doing well under a single hydra 52 (one hydra 52 covers a 36 inch tank). But after a lot of reading and seeing what the show case tanks are doing I doubled the amount of leds to two hydra 52 on my 55 gallon. Turned down the intensity so not to melt my corals and yes there is a major difference. So to do it right. You need a lot of LEDs. I'm starting to think that's why the cheap chineese boxes work. Because of their low cost of entry people tend to purchase more of them for their tanks and get better coverage. High end LEDs make it harder on the pocket to do the same. My two cents

 

[SPotter]

I'm starting to think that's why the cheap chineese boxes work. Because of their low cost of entry people tend to purchase more of them for their tanks and get better coverage. High end LEDs make it harder on the pocket to do the same. My two cents

Totally agree with you on this! On my last tank I had a Pacific Sun LED/t5 fixture and struggled with it for over a year before finally giving up on it. My main tank now is MH/T5 and I love them but I did put up a programmable, full spectrum chinese LED over one of my frag tanks and I have now called that section of the tank my "Magic Garden"! I am amazed at the growth and color of the sps under those lights. Unfotunately, on a tank my size I would need 8-10 of them to get the coverage I need.

 

[JPMagyar]

What do you consider as "very expensive equipment"? I've seen spectra of LEDs (e.g., PC amber) on a $20k integrating sphere spectrophotometer and what I have seen with my own eyes doesn't agree with your statements. One of my colleagues in the physics department here studies novel phosphor coatings for LEDs and we've talked LEDs quite a bit.

I'd like to hear some specifics (your studies with specific pieces of equipment) and/or publications you can provide to back up your claims.

For the record, my tank is T5/LED (soon switching to MH/T5 Cebu Sun) and doesn't hold a candle to yours. I'm not pro-LED, but I'm also not following your arguments.

Once long ago in a galaxy far far away I worked briefly in the field of semiconductor doping for a factory in Massachusetts that has long since moved. My job was to determine the energy input necessary to achieve a certain doping depth.

I do not study LEDs nor do I have access to expensive equipment. What I do have is a good knowledge of how LED light is produced and how metal halide light is produced.

If you have a friend in a physics department who has access to the right equipment ask him or her to plot the photon flux of individual wavelengths for one single LED, not one CREE LED but one individual P/N junction. That is the only way to truly "see" and understand what is going on with the photons produced by LEDs. The spectral "spike" from an LED is much more intense than the multiple spikes you get from a metal halide or a T5. Yes, yes, and yes. You can mix LEDs and spread them out and come darn close to the output of a metal halide, but that is NOT how most manufacturers are producing LED fixtures today. It's not about producing photons. It's about producing wavelengths of light that optimize photosynthesis. I don't need expensive equipment to tell me that corals grow better under today's metal halide and T5 fixtures. Does this mean LED technology isn't improving and might not someday overtake metal halide bulbs? No of course not. It just means that today, right now, LED fixtures available to the average hobbyist are deficient in their spectral output AND often deficient in how they spread their output, and this is a direct result of the physics of LED light production.


Here is a chart showing the wavelengths associated with the most commonly used LED materials. Notice that they give a range but no where on the internet will you find a plot of photon flux for individual wavelengths in that range. Regardless you can see that individual LED types have generally narrow ranges. Also note that the LED with the broadest range (RED) actually can be made with 4 different sets of materials and the chart doesn't break out the range for each subset which is narrower than the set as a whole. Notice also that the "white" LED which is listed as having a "broad" spectrum uses phosphor excitation and not pure LED light. Excited phosphors are how T5s produce light but T5s use a mix of phosphors to increase spectral output. Perhaps that will prove to be the answer for LED fixtures, but then they still need to solve the issue of spread. :beer: