Anyone Thinking of Dumping LEDS and going back to Halides

[mussel and hate]

It appears that some folks may have missed your point... So I will rehash.

White that is derived from mixing RGB has nothing to do with real white light. You ca get "white" from 3 spectral peaks that have zero ability to drive photosynthesis... It is not WHITE your brain just interprets it that way...

There is so much bad information in this thread that I would not even begin to know how to correct it.

Somebody said that a pile of LEDs are pretty much the same as a MH bulb... Just a bit different with regard to peaks...um no, not even close. A MH bulb emits light from a plasma arc, it by definition is continuous spectrum. It may have peaks, but there are no gaps in wavelengths. A pile of LEDs emits a very narrow pile of peaks with gaps in between.

Phoshpors? T5 and LED... Again worlds apart. The fluorscent bulb uses a mercury arc to create UV light. The UV drives the phosphor stokes shift. The same phosphors can not be used for LEDs because of the input wavelength difference. Decades of research went into FL phosphors. White light was a priority, as there is no way to create a reasonable RGB FL bulb to produce white light. In the LED world things are different. Read on....

I will say it again, almost everything we use in this hobby is a direct purchase from industrial stock. While white led phosphors are getting better, there is little drive for better white rendering when it is easier to build an RBG emitter that can be tuned to emit whatever pleasing color is wanted. The RGB emitter combo does solves the color rendering issue for humans, but is (again) devoid of much the spectral content required for photosynthesis. Not sure why so many folks are having trouble swallowing the reality... Until there is an industrial demand for LEDs with broad spectrum phosphors... There will be no LEDs with broad spectrum phosphors. Agricultural applications got their uv and deep reds, they don't really need whites, as they are looking for growth, not aesthetics and growth. Nobody in industry cares about my or your aquarium

Am I to conclude from your statements that white LEDs do not stokes shift blue/violet to higher frequency light as fluorescent lamps do? Because last time I checked they seemed to do just that.

I don't believe anyone is claiming that a three peak RGB led array approximates sunlight. Your just setting up a strawman.

I'll agree that LEDs do not produce light anything like HID lamps do, that is totally different. But in my decades of reefkeeping using every light source available I've had the same successes and failures with specific corals regardless of light source. Water chemistry and feeding seem to be the determining factors for me. No lamp be it MH or anything else has the magical properties to overcome alkalinity swings, waste accumulation or nutritional deficits which in my experience and opinion are the most challenging hurdles.

There are some really nice tanks here such as Joe's but pictures of beautiful reef displays don't actually constitute proof of an argument. I know that's how it's done on the web these days but that is not reason...

MH, fluorescent and LED all work, what you prefer is another matter.

 

[BeanAnimal]

Am I to conclude from your statements that white LEDs do not stokes shift blue/violet to higher frequency light as fluorescent lamps do?

That is not at all what I said. I said the base wavelengths are very different and therefore the required phosphors are very different. FL phosphors have both decades of development and came at a time where quality where there was a need for pleasing output. LED phosphors are in their infancy and due to the ease of RGB mixing (among other things) there is less drive to produce true full spectrum phosphors for the emitters.

I don't believe anyone is claiming that a three peak RGB led array approximates sunlight. Your just setting up a strawman

no just making sure the point is not lost. It is repeated in many of these threads. Most folks mistake (with the help of vendors) Some combination of RGB for "full spectrum" light.

I am not going to address the rest of your comments, as they are outside of the scope of my point.

 

[oreo57]

and due to the ease of RGB mixing (among other things) there is less drive to produce true full spectrum phosphors for the emitters.

That is more of an opinion than fact.
Really bad translation but gets to the point:

White LED is many industry analysts or LED industry in mind quite promising emerging parts products. Of course, the reason is that, in the global energy resources is quite limited concern background, white LED as prescribed in the foreground of the market attracts global attention. In Europe, the United States and Japan and other advanced countries have devoted a lot of human and financial resources, establish special orgnaization to promote white LED research and development work. Why do the white LED will be considered for future star parts products, this course with his special advantage or advantages, there is considerable relationship.

https://www.electrochem.org/dl/interface/wtr/wtr09/wtr09_p032-036.pdf


From the very moment they made the first white LED, the race was on.. (WHY they wanted to make it in the first place is a hint to the perceived need)

RGB for CRT replacement.. sure.. but LED for lighting.. "pure" white was and is the only goal.
CRI metrics even needed to be changed due to the "problem" of white LED.
http://www.mouser.com/applications/lighting-cri/

RGB held nothing back. Patents and tech held white back, and plenty of cash has been dumped in to "fix" it.

coupled w/ a "good enough" philosophy..

What is good for you?
For us companies developing LED modules, it is much easier to develop CRI80 as a standard, due to easier and better access to phosphor solutions. However there are solutions where CRI 90 or 95 are necessary to implement such as in Medical lighting or High-end Retail Lighting. Meanwhile, CRI 80 has to have some red in it to be good and then it will be good enough to be used in home environment or retail business. So, what is good enough for you?

But this has nothing to do w/ RGB=W , which from the moment of it's use has has a horrible CRI index. Human perception allowed poor color rendering to appear "good enough".. while those in the know, so to speak, knew it sucked. Luckily for the industry not as bad or in the same range as the fluorescent skin tone rendering problem. That "good enough" thinking "may" have retarded development but the industry knew, and knows high CRI (almost by def. broad spectrum) high efficiency and cheap to produce LED is one of the holy grails ....

young, maybe, driven certainly:

The potential of LED technology to produce high-quality white light with unprecedented energy efficiency is the impetus for the intense level of research and development currently supported by the U.S. Department of Energy.

http://energy.gov/eere/ssl/led-basics

The CRI has been found to be inaccurate for RGB (red, green, blue) LED systems because it's poor at predicting the quality of the appearance of saturated color objects, and doesn't correspond well to human perception of color quality.

And for fun:

well-designed LED fixtures can deliver light efficiently to the intended location. In contrast, fluorescent and "bulb" shaped incandescent lamps emit light in all directions; much of the light produced by the lamp is lost within the fixture, reabsorbed by the lamp, or escapes from the fixture in a direction that is not useful for the intended application. For many fixture types, including recessed downlights, troffers, and undercabinet fixtures, it is not uncommon for 40 to 50% of the total light output of fluorescent and incandescent lamps to be lost before it exits the fixture.

 

[BeanAnimal]

More opinion than fact? What drives product development? Demand does. That demand comes from industry. Right now the demand is for cost effective LED replacements for high bay and consumer luminaries. While CRI is of some concern, Lumen output and fixture cost are the driving factors. Nobody said that high CRI LED phosphors are not being worked on, they are. They are just not mature compared to FL phosphors. We (us, they, whatever) are also up against the "it's good enough for the purpose" mentality. Again (5th time?) industrial demand drives most product development, not niche need. Look how few high CRI CFL bulbs are produced and consider that the phosphors already exist. Cost to produce vs industrial demand....

You mention the medical field and high CRI LED phosphors. That is one area that will help drive development, but like most things, not until demand rises enough to make development and adoption cost effective. This, and the photographic sciences will help drive innovation of these phosphors, but again (6th time?) that niche is much smaller than the overall industrial demand that could pretty much care less.

I am very familiar with the PDF (Anant Setlur) you linked to. I find it almost laughable that you are attempting to use it to support your position, when in fact the very substance of the document is in the context that progress has been made, but there is a long way to go.

I am not an "LED hater" and in fact, EVERY lamp in my home is LED except for the oven bulb. That means, can lights, lamp bulbs, sconce bulbs, outdoor floods, etc. My tank has (3) Radion fixtures above it that used to be 150W Halides. Just because I have adopted them does not mean that I have to lie to myself about their benefits, efficiencies or aesthetics.

The Radion color rendering (to me) is hideous compared to (any?) MH lamp, and/or a well balanced T5 setup. I abhor the disco effect and am rather sensitive to the oddity of the non continuous spectral output. I am not likely to "break even" on the power savings vs purchase cost, but welcome the lower monthly bill in context to the *****ing that I heard otherwise every month from the warden. I.E. I would pay YOU $50 cash a month to lower my electric bill by $30. It is all a matter if perception (no pun).

The LEDs in my home: Again, they will NEVER pay for themselves but lowering the monthly bill keeps the warden off my back. They are less trouble than CFL bulbs and, in general, have a better overall color cast (regardless of CRI). They last a lot longer and produce less heat. The BUZZ from many does drive me insane but they don't burn out when upside down. They don't take 10 minutes to come up to full output in cold weather and they don't break.

In any case, you are conflating a lot of "fun facts", press release platitudes and disparate information to derive a point... In reality, the "state of the art" is what industry uses in bulk, not what is on the bleeding edge or in a niche lab. That stuff will certainly trickle down, but only in so far as it makes sense to industry in general. Do you see aerogel insulated homes or buildings yet? Nope! Ask yourself why, but be careful of the answer....

 

[markalot]

Everyone needs to stop the personal attacks. If you get snarky I assume you have no facts to back up your opinion.

I firmly believe that once the coverage and balance issues are solved then it will become personal preference as to what bulb or color combination of LED's will color up corals the best. As someone answered above, the Radium was an accident. It's not even close to sunlight (even at depth) and it's not even close to smooth. We know it works and works extremely well so that's a great baseline. If you're looking for something that better mimics sunlight underwater then LED clusters can come a lot closer so a smooth spectrum without large gaps. In my opinion a smooth spectrum is not really the answer here anyway since T5 and MH have lots of gaps and very un-smooth spectrums.

So, LEDs can grow corals, right? They can, but only the side directly facing the LED is getting the proper light and that, IMO, makes for an unhealthy coral and might actually be part of the color problem as well. In the wild the sun moves across the sky (the earth is flat, right? ). I suppose we could put LED's on conveyor belts and move them across the tank.

But seriously, IMO T5's or MH with the proper reflectors duplicate the fact that corals get light on multiple sides during the day. This makes corals more healthy, but does it effect coral coloration at all? Do we know for sure?

I've heard multiple times now that the spectrum presented for LED fixtures is smoothed, but I haven't found any proof to back that up. Did I miss it? It's got to be out there somewhere? I believe it is fairly smooth, but even if it isn't MH and T5 has shown us that smooth is not a requirement, which is why I really think this is a coverage and blending issue as far as acro health is concerned.

Coral color? I find it fascinating that the Radium can bring out such awesome colors and I don't believe we know why. To say it is the perfect bulb with the perfect spectrum is to believe that this accident just happened to land on the perfect balance for acropora and there is no better light source. The odds of that being true are pretty low.

But that's just my opinion.

 

[oreo57]

Your opinion that reads:

LED phosphors are in their infancy and due to the ease of RGB mixing (among other things) there is less drive to produce true full spectrum phosphors for the emitters.

is mostly innuendo with no facts to back it up except "general perceptions" that can be used for anything.....

If I was a manuf looking at putting a light (any light) together and my choice was 3 different diodes, different electrical charactheristics ect vs one diode, one spec.. which would I choose???
The word "duh" comes to mind..
RGB "may" have had some sway pripr to the introduction of "white" led's but as soon as those apperred they were gone.. Except for clown strips on ebay
THAT alone tells you "demand" was there..

Haven't seen anyone selling rgb LED bulbs except for mood or novelty lighting.. some demand is pretty obvious...

Industry "demanded" a white light .. RGB was ONLY used because it was the ONLY way to do it, now relegated to novelty status (ignoring TV use).

 

[Wazzel]

LEDs have the power and spectrum to grow corals and do it well. I see it in my tank every day. I use them and like them but know they are not perfect, but neither are Mh or T-5.

IMO the only major design issue is coverage. If the high end builders, ETM and AI I am speaking to you, would get off the large centered puck concept and go to smaller spread concept it would accomplish what adding reflectors to Mh and T-5 accomplished.

The other real issue is operation parameters. I have no ideal on how to get over that hurdle. Maybe just user hours and sharing knowledge will be enough.

 

[Cyberdude]

LEDs have the power and spectrum to grow corals and do it well. I see it in my tank every day. I use them and like them but know they are not perfect, but neither are Mh or T-5.



IMO the only major design issue is coverage. If the high end builders, ETM and AI I am speaking to you, would get off the large centered puck concept and go to smaller spread concept it would accomplish what adding reflectors to Mh and T-5 accomplished.



The other real issue is operation parameters. I have no ideal on how to get over that hurdle. Maybe just user hours and sharing knowledge will be enough.

150% agree. Coverage is the major issue. Is why cheap Chinese LEDs works. Because they don't break the bank and you can cover your tank with them.

I just doubled to two hydra 52 on a 55 gallon for total coverage. And fisnlly see a major difference.

 

[markalot]

I think most (not all) agree with that, but I think most of us? also agree so far no LED combination has been able to replicate the coral colors that can be brought out by the Radium bulb. Right?

 

[Wazzel]

I think most (not all) agree with that, but I think most of us? also agree so far no LED combination has been able to replicate the coral colors that can be brought out by the Radium bulb. Right?

Why does that matter? The colors brought out by radium bulbs are not natural anyway. It is just some random "standard" that developed somehow over the past few years.

I like my current LED tank as much as I liked my MH/VHO tank. They are a little different. Some coral liked the MH better some like the LED better.

 

[Wazzel]

150% agree. Coverage is the major issue. Is why cheap Chinese LEDs works. Because they don't break the bank and you can cover your tank with them.

I just doubled to two hydra 52 on a 55 gallon for total coverage. And fisnlly see a major difference.

I have a section of my scap that is steep and the corals on it do not get as much light as they need. Knowing what I know now I would have done things slightly different. I should either re-scape or get another light, but neither is real appealing right now. I am actually hopeing my tank continues to do well and I can talk the wife into agreeing to a larger tank. At that point I will make good use of what I have learned in the past year to lay things out better.

 

[markalot]

Why does that matter? The colors brought out by radium bulbs are not natural anyway. It is just some random "standard" that developed somehow over the past few years.

I like my current LED tank as much as I liked my MH/VHO tank. They are a little different. Some coral liked the MH better some like the LED better.

I'm not sure it matters, it's personal preference for sure, but it's why many switch back and will want to hang on to the Radiums as long as they can. I think it would be nice if we could somehow duplicate the performance with LED.

 

[Wazzel]

I'm not sure it matters, it's personal preference for sure, but it's why many switch back and will want to hang on to the Radiums as long as they can. I think it would be nice if we could somehow duplicate the performance with LED.

This is visual hobby so personal preference is a very valid reason to use this light or that light. I wish people would be comfortable with just saying "I like x over y" and not over exaggerate little things or straight out make things up to justify their preference.

 

[oreo57]

I'm not sure it matters, it's personal preference for sure, but it's why many switch back and will want to hang on to the Radiums as long as they can. I think it would be nice if we could somehow duplicate the performance with LED.

seems more of need to remove something in LED than add..
The Radium spectrum is really rather simple..

One thing to note is the lack of lower blue (i.e purple) compared to other 20000k MH's
as a simple though experiment "if" I had thecash and want to emulate the Radium, I'd start w/ the 5600k Yuji's at .5w to generate as flat of a spectrum as I can and add colored LED's
for the spikes..

The fact that "normal" whites aren't relatively flat across the 460-660nm spectrum seems on first glance, to be the problem..

 

[Wazzel]

That would be the big green hump in the Cree XP-G2 white LED. Until someone manufactures a white without that it is not happening.

 

[oreo57]

That would be the big green hump in the Cree XP-G2 white LED. Until someone manufactures a white without that it is not happening.

look at the 5600k spectrum here:
https://cdn.shopify.com/s/files/1/0...5-5730-Specification.pdf?15345788962182890367

450-630 "relatively" flat...
What do you think about that one... Granted only available in .5W

 

[overexposed]

Haven't seen anyone selling rgb LED bulbs except for mood or novelty lighting.. some demand is pretty obvious.

Look no further than AI and EcoTech, the most prolific lights in our hobby.

In my opinion a smooth spectrum is not really the answer here anyway since T5 and MH have lots of gaps and very un-smooth spectrums.

While smooth might not be necessary, the common LED fixtures from the above manufacturers are actually missing very large gaps in their spectral output. When people refer to smoothing, they are referring to the fact that the lines on many of those spectral plot graphs are acting like fabric draped on top of tent poles. A Radion XR30W Pro has the following diodes, each of which has a spectrum that falls off about 5nm either side of its stated output:
Cool White: the only broad spectrum diode
Deep Blue
Blue
Green
Hyper Red
Yellow
Indigo
Violet

If you look at the spectral plot, it appears that the intensity between blue and green remains steady at approx the 10% mark of the graph. In reality, there is no output between say 480 (blue) and 550 (green) except for what might be given off by the cool white. The blue and green diodes only have output from about 470 to 490 and 540 to 560, sharply spiking in the middle of both those ranges. According to the chart, there is a 10% output at 510nm that simply doesn't exist. The line should drop to zero. This is what people are referring to as the smoothing effect.

I took a look at that Yuji website and they are just using either a blue or violet diode coated with various phosphors. Assuming (perhaps incorrectly) that any other white LED is developed in a similar fashion, then I would suspect that there would be similar zero-output gaps between whatever spectrum the excited phosphors generate.

This makes corals more healthy, but does it effect coral coloration at all? Do we know for sure?

It effects coral colouration where it matters most - the part we look at!! (the sides of our corals)

 

[shermanator]

Sorry, never mind, I misread.

 

[Wazzel]

look at the 5600k spectrum here:
https://cdn.shopify.com/s/files/1/0...5-5730-Specification.pdf?15345788962182890367

450-630 "relatively" flat...
What do you think about that one... Granted only available in .5W

I am not a lighting expert, but still looks not flat enough.

 

[GroktheCube]

I agree that coverage is probably the bigger challenge than spectrum at this point in time.

I think lenses that blend color better combined with reflectors similar to those used with MH and T5 will be able to rectify that problem in time.