Dropped LED to go back to MH for the second time :/

[LordDarth Bane]

The bottom line is that the only savings from ANY light source is by cutting spectrum and keeping intensity high (LED) or just cutting intensity (less of another source... 250W Halide vs a 400W Halide, for example). A quantum from a LED with a wide spectrum and the same amount of energy will take the same wall power as a MH or any other source. There is no way around this. None. The science is there to produce LEDs that are broad spectrum, but there is no energy savings and some of the early wide spectrum diodes use more energy (they will get better).

I think that one positive that LED brought is a sense that most folks never needed as much power as they might have once had. A mixed reef did not need 4x400W MH and a pile of T5s at 1500W to do quite well. Sure, LEDs can do that job for 1/3 the wattage, but so could lower wattage metal halides or less T5 bulbs.

I am no way a quantum physicist but I think you missed something. Have you ever considered their efficiency? Eg lumens per watt.

MH is less efficient as they are hot. More electrical energy is converted to heat energy, resulting in less light energy.

There is no way a 250W MH, can produce as much light (lumens) as a 250W T5HO system, or LEDs.

Simple law of conservation of energy.

 

[jda]

It does, actually. They produces light waves in the IR range. This is where the heat comes from, not a dead-short or electrical rush type of heat more than the same wattage of any other product (all have some), so your application of that law is not applicable. LEDs have this too when power supplies and diodes get hot from electrons racing, but there is no IR, so less heat - it is also spread out over more diodes. If there was no IR, then 100W of MH electrons and LED electrons would be identical in hot power supplies and bulbs/diodes. For sure, some of the IR spectrum is not all that usable to most corals (if not all), but they are light waves nonetheless that took the same power to create the quantum.

I get where you are coming from, but it is misleading by those who have offered it before. Once you realize that the heat is from IR, which is wave/light output, then watt to watt output being equal starts to make more sense and then you can dial down to how much power being put into IR is wasted - there is some. This is where the inequality lies, but not as much as some think.

The only reason that they measure differently is the tools available for most to measure and the reliance on some using those tools as absolute - while they are the best that most have access to, a real manufacturer that can rent or use a good tool should not be relying on them. Or, they only measure a small piece of the spectrum - sure a light made up of nothing but 5.5k diodes will have more lumens per watt than a light putting out from 4500 to 7000 but only reading at 5.5k. Using an integrating sphere (usually about $20-30K) with all light sources at 100% output and capturing all of the waves, any light sources will have the same ratio of radiated watts to input watts. If you cut down the IR range over 720nm, then MH will waste 2-6% depending on the bulb since this is most likely useless waves that are pure heat.

In the end, if you have a real tool to measure, then a MH is 2-6% less efficient in useful spectrum than a LED (bulb dependent) - not nearly what people would have you believe. I never tested any T5s for their IR output since they won't fit in an Integrating Sphere. Here is where it gets crazy... to think about how even though LEDs have nearly all of their spectrum (power) in the useful range, how inefficient are they for growing coral since the concentrate their wattage on a handful of large peaks of spectrum ranges and leave huge gaps between. If you have to fill those ranges with other lights (most use T5s), then how wasteful is the excess output for that handful? I don't know to know this, however. This is a harder concept for most to grasp with more nuance and the "pro LED" folks can just say "heat" and people will get their somewhat off-basis argument.

I probably did a bad job explaining this... sorry. Basicly - 100W of "conservation of energy" heat will produce the same heat for any light source since it is dependent on electrons that are fixed - MH is hotter because of light waves in the IR range.

 

[zsuman101]

Here is my unprofessional opinion on the lighting matter.
MH works on all level - high heat, high energy cost
T5 works on all level - medium to high heat, high / medium energy cost
Leds works on all level - Highend gear - medium to low heat / medium energy cost providing it is getting good light spread.

All will grow corals in sps tank to a certain degree. I feel the LEDs can improve over time with efficiency and design challenge.

It's true you can do it with leds, you just need a radion for every square foot of reef, then you have to hang them 3 ft or more feet above the tank to get the proper mixing of colors before the light hits water. And since they're so far off the water you have to crank them up , with that said there is no wattage saving, if anything it's more. I have and use mh, t5 and radions. I believe the magic is inside those radium halide oozing all those wavelengths homogeneously (is that a word) and Leds just need to be implemented in a different way i.e. much higher up and many many units to do it right by sps standards. BTW, ime nothing beats my radium halide reef, period ...... zsu

 

[cobra2326]

It does, actually. They produces light waves in the IR range. This is where the heat comes from, not a dead-short or electrical rush type of heat more than the same wattage of any other product (all have some), so your application of that law is not applicable. LEDs have this too when power supplies and diodes get hot from electrons racing, but there is no IR, so less heat - it is also spread out over more diodes. If there was no IR, then 100W of MH electrons and LED electrons would be identical in hot power supplies and bulbs/diodes. For sure, some of the IR spectrum is not all that usable to most corals (if not all), but they are light waves nonetheless that took the same power to create the quantum.

I get where you are coming from, but it is misleading by those who have offered it before. Once you realize that the heat is from IR, which is wave/light output, then watt to watt output being equal starts to make more sense and then you can dial down to how much power being put into IR is wasted - there is some. This is where the inequality lies, but not as much as some think.

The only reason that they measure differently is the tools available for most to measure and the reliance on some using those tools as absolute - while they are the best that most have access to, a real manufacturer that can rent or use a good tool should not be relying on them. Or, they only measure a small piece of the spectrum - sure a light made up of nothing but 5.5k diodes will have more lumens per watt than a light putting out from 4500 to 7000 but only reading at 5.5k. Using an integrating sphere (usually about $20-30K) with all light sources at 100% output and capturing all of the waves, any light sources will have the same ratio of radiated watts to input watts. If you cut down the IR range over 720nm, then MH will waste 2-6% depending on the bulb since this is most likely useless waves that are pure heat.

In the end, if you have a real tool to measure, then a MH is 2-6% less efficient in useful spectrum than a LED (bulb dependent) - not nearly what people would have you believe. I never tested any T5s for their IR output since they won't fit in an Integrating Sphere. Here is where it gets crazy... to think about how even though LEDs have nearly all of their spectrum (power) in the useful range, how inefficient are they for growing coral since the concentrate their wattage on a handful of large peaks of spectrum ranges and leave huge gaps between. If you have to fill those ranges with other lights (most use T5s), then how wasteful is the excess output for that handful? I don't know to know this, however. This is a harder concept for most to grasp with more nuance and the "pro LED" folks can just say "heat" and people will get their somewhat off-basis argument.

I probably did a bad job explaining this... sorry. Basicly - 100W of "conservation of energy" heat will produce the same heat for any light source since it is dependent on electrons that are fixed - MH is hotter because of light waves in the IR range.

If I may, this is a misleading way of looking at things. Heat is emitted across many different wavelengths, generally above the visible spectrum (> 700nm). Including those wavelengths in a measurement will do exactly what you said, it will make all light sources look equal. Incandescent bulbs will look the same as LEDs, fluorescent bulbs, etc.

If "heat" is confusing (I don't think it is), you can use the concept of thermal radiation https://en.wikipedia.org/wiki/Thermal_radiation. It's radiation in the same sense as the usable light emitted by a bulb, but that's where the similarities end:

The incandescent light bulb has a spectrum overlapping the black body spectra of the sun and the earth. Some of the photons emitted by a tungsten light bulb filament at 3000 K are in the visible spectrum. Most of the energy is associated with photons of longer wavelengths; these do not help a person see, but still transfer heat to the environment, as can be deduced empirically by observing an incandescent light bulb. Whenever EM radiation is emitted and then absorbed, heat is transferred. This principle is used in microwave ovens, laser cutting, and RF hair removal.

 

[jda]

Cool. Then if we can agree that it takes the same energy to create the same radiated watt, then this is progress. Then, sources can start to eliminate an analyze the unusable spectrum and call it a day. Like I said, for a handful of Reef MH bulbs, it was 2-6% waste about 720nm, bulb dependent. If the difference in radiated watts was 2-6% in the 350 to 720 range, don't you think that people would see that differently than what they are being told now? It certainly matches more anecdotally with what people say when they have to use 2-3x the panels to replace a gas bulb for high light coral (two panels at 50-60% being closely equal to one MH at 100%).

What happens when people say heat, is most folks think of normal "electronics heat." They don't think of IR. When you look at IR emitted by a REEF MH bulb, it is there, but not in super huge quantities.

I am not saying that IR Heat and this spectrum should not be considered. It certainly should. ....but the "3.5x more lumens per watt" that is thrown around is just not even close... and people buy new equipment based off this believing it to be true.

We did not test a regular incandescent bulb, but tungsten filament and a gas are pretty far apart for output. You have piqued my interest, though... Just a quick google search for spectrum shows one at 400 to 750 nm (which does not seem right) and another says that they go up 2500nm (which does not feel right either). Maybe we can test one next time.

 

[Wiskey]

jda, thank you for taking the time to explain this! I was thinking that some light with MH was wasted to heat, but reading that it's IR which is a type of wave makes a ton of sense! It's really interesting that only a couple percent is wasted to pure heat. I love being efficient, and I couldn't stand the idea that MH was "Wasting" all this energy, it makes a big difference if I'm told its producing a wide spectrum of light similar to what the corals see in the wild, some bands of which I can't see.

I'm using all T5 now and going from T5/LED to pure T5 was a good move for me. I would love to upgrade to a 120, or 180 and when I do the choice will be between MH/T5 and all T5.

Subscribed. This is one of the most informative threads I've read in a long time.

Whiskey

 

[Dugless]

This thread reminds me why I gravitate to the SPS section. Good stuff here.

 

[LordDarth Bane]

Be it simply called "heat", or "infrared heat" in the electromagnetic radiation form, to try to say that MH is as efficient in using electrical energy to produce "light" because it is still producing lots of "light" that you couldn't see! In the form of infrared which is above the visible light wavelength.......

Do these really matter? Do you think our corals need infrared? Do you still remember that when light goes into water, colours are lost every 10m, with red first? How deep could infraRED go? Do corals in the sea actually receive lots of infrared? I'll just leave it here.......

Appreciated all the informative replies. Cheers.

 

[jda]

I am not saying that IR light is a good thing. ...just saying that there is not nearly as much there are what people say and think.

I don't know that anybody knows if our corals need IR. Some of the shallower corals do develop pigments to reflect IR (like sunscreen), so it can help with natural coloration. There are acres of SPS that sit out of the water for some of the day. However, I don't know if I would add it to a light source missing it. (laugh if you want about IR being responsible for color, but just a few years ago, there was laughter about adding UVB to LED panels to color corals better)

All of this starts to make sense where some really smart folks have opined that in their experiences that there is no savings in wattage to light a tank with the same (or as close to the same) results. Dr Joshi has an outstanding reputation (at least I have never hard anything bad said about him) and has this opinion. If you factor in that a reef MH bulb will lose 2-6% to heat and all of this is quite believable.

 

[cobra2326]

So, BRS did their review of the Kessil A360W and I'm going to go out on a limb and say, even at 100%, it's really not enough PAR for SPS. At 12",
PAR peaked at 170 and averaged 145. If you were running them at 35% intensity, that's < 100 PAR at 12". With two, you might get some boost from overlap but I'd love to see actual measurements. Not to mention the hotspot issues and other problems.

Anyway, if you're interested in trying to run Kessils, watch the video. They cover a lot of things, and it looks like you'd need 2 placed close together, or 3+ to really get enough PAR. With most high-end T5/MH Tanks getting peak PAR in 500-600 range, you'd need at least 4.

https://www.youtube.com/watch?v=wavz8K63-Oc

 

[cobra2326]

Cool. Then if we can agree that it takes the same energy to create the same radiated watt, then this is progress. Then, sources can start to eliminate an analyze the unusable spectrum and call it a day. Like I said, for a handful of Reef MH bulbs, it was 2-6% waste about 720nm, bulb dependent. If the difference in radiated watts was 2-6% in the 350 to 720 range, don't you think that people would see that differently than what they are being told now? It certainly matches more anecdotally with what people say when they have to use 2-3x the panels to replace a gas bulb for high light coral (two panels at 50-60% being closely equal to one MH at 100%).

Wouldn't you say that PAR and spectral analysis are a much better way to compare things?

I am not saying that IR Heat and this spectrum should not be considered. It certainly should. ....but the "3.5x more lumens per watt" that is thrown around is just not even close... and people buy new equipment based off this believing it to be true.

I totally agree with this. Although some of the latest-gen LEDs (emitters, not necessarily fixtures) do seem to have a slight efficiency boost over MH or T5, it's not much (30% vs. 25% IIRC from one of the studies you posted and others I've read). I can pull actual numbers, but I don't think that's the point. You're not going to get the same results with 100W of LEDs as you do with 250W of MH. Maybe 225W of LEDs, but only if you properly space them to account for shadowing, and run a modern fixture with full-spectrum.

 

[dadummy]

years ago they told me you can't grow SPS under VHO, that was a false statement. Then the T5 tube came along which I was also told cannot grow SPS, wrong again fella's. Once again LED's started showing up and the veterans said you cannot grow SPS under LED, well wrong again, they did grow...BUT!!!!.. I haven't tried to grow SPS Acropora especially under power compacts, and don't feel the need too, but with the right application and water quality, I am sure it could be done.
A guy at a LFS has SPS, Montipora, A. Tenuis *growing in a very small cube maybe 3 gallons with a Par 38 bulb over it. The only equipment on the tank is a bubbler. Basically, a piece of rigid airline tubing putting out a couple bubbles a second submerged halfway down the cube. No fish, no food, occasional water change and top off, that's it!! Pretty cool little experiment, curious to see how long the corals survive, been a couple three months so far.
Don't know where I am going with all this but a successful reef has more factors than lighting alone