What's in a Metal Halide spectrum? What's the secret spectral sauce?

A. grandis · Mar 3, 2023

luxdium said:
There was never a question that halides had or did not have any UV or any other color, but how much? This experiment was actually conducted on December 29-30, 2022, before any such videos came out. There's a dearth of high-resolution data on Metal Halides and spectral analysis. To jump to the conclusion that their success hinges on a particular band is myopic. What we forget is the same elements used to produce the 450nm metal halide peak are also found in LEDs, eg. Indium and Gallium. For LEDs, varying the ratios controls how blue or violet-shifted they are.

Is it really the spectrum or is it the distribution, or is it something else, or is it a combination? Has anyone successfully run a lamp over a system without a reflector?

It is known that Kelvin is approximated from a coordinate system, but goes awry if the light source is not a true blackbody, or as some say, "Planckian."

It is the essence of the metal halide technology.
Light produced by gases, like the sun.
Spectrum and intensity, very similar to the sun.
Distribution and delivery, very similar to sunlight.
Halide power.

I know this is not supposed to be a "LED vs halide" thread, but it if it's to find that "missing link" and apply to your LEDs, it's going to have 100+ pages and will go on until someone comes and say it's going to be impossible for any LED to reproduce halide and it comes to that personal preference. Sorry, it sounded like you want to try to "mimic" halides to it's best in order to find that "secret spectral sauce".
It comes down to different technologies and different essences in the production of light to start with. It comes in a package of essences.

A. grandis · Mar 3, 2023

Do you know what I like the most in this thread? Is the proof that halides should still be in many ways the standard of what we should look for in reef lighting for optimal results comparing to sunlight, if those results is what you are looking for.

Power to you both for opening this and showing the data. Thank you!
Please go ahead with more info.
This is a good thread.

oreo54 · Mar 3, 2023

Soo which do you judge is more "daylight" like?
Grey shade is "sunlight"
Note I did cheat a tad..There are a whole 2 different diodes in one..

Even more cheating. I suppose I could add a quartz heater to it to add some long IR.

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Thales · Mar 3, 2023

Shallow corals that get exposed are adapted to that environment, and that environment is often a war zone. Most of the corals we keep do not come from the areas that get exposed. I don’t think such corals are a good talking point for this kind of discussion.

A. grandis · Mar 3, 2023

The main subject is UV. It doesn't get too far down. Still we can find amazing healthy organisms in such environment. That takes off those arguments about UVR as killer machine.
The great majority of the coals in this hobby are in that shallow water environment.
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jda · Mar 3, 2023

Thales said:
Shallow corals that get exposed are adapted to that environment, and that environment is often a war zone. Most of the corals we keep do not come from the areas that get exposed. I don’t think such corals are a good talking point for this kind of discussion.

You know that I respect you and all, but a lot of the acropora that I have was collected exposed at low tide or just a few inches under the water. I watched the guy collect it - they were also collecting species to mount and aquaculture. Tenuis, plana, millepora, humulis, many stags, TONs of hyacinthus (tables), etc. The guys showed me where they took a 12" hunk out of a huge millepora colony and in 2-3 weeks, the gap was almost closed. They were standing in waist deep water and the coral was exposed. I don't care about the tidepool corals and all of that - they are different and maybe that is what you are thinking about with the war zones. I am talking about the miles and miles of exposed acropora and stony reefs away from shore like in the photo that I posted.

I want to know what makes these thrive. I want to duplicate it as much as I can. Some day, I will have solar tubes with some supplements, but my current house does not allow it. I don't care about all of the other posts and stuff in this thread. Those acropora GROW out of the water and thrive.

oreo54 · Mar 3, 2023

For no particular reason .. A fun fact.
Non- photosynthetic for the most part
(all?)

Corals are best known to thrive in warm shallow waters, but almost 66% of coral diversity (3,336 of the 5,080 known coral species) is found in waters deeper than 50 meters [16]. Percentages of deep-water coral species are greater for stylasterid corals (89%), black corals (75%), and octocorals (75%), but as much as 41.5% of the 1482 living scleractinian corals (the major group of hard corals) are also found exclusively in the deep sea.

PSXerholic · Mar 3, 2023

Thales said:
Shallow corals that get exposed are adapted to that environment, and that environment is often a war zone. Most of the corals we keep do not come from the areas that get exposed. I don’t think such corals are a good talking point for this kind of discussion.

Thales · Mar 3, 2023

jda said:
You know that I respect you and all, but a lot of the acropora that I have was collected exposed at low tide or just a few inches under the water. I watched the guy collect it - they were also collecting species to mount and aquaculture. Tenuis, plana, millepora, humulis, many stags, TONs of hyacinthus (tables), etc. The guys showed me where they took a 12" hunk out of a huge millepora colony and in 2-3 weeks, the gap was almost closed. They were standing in waist deep water and the coral was exposed. I don't care about the tidepool corals and all of that - they are different and maybe that is what you are thinking about with the war zones. I am talking about the miles and miles of exposed acropora and stony reefs away from shore like in the photo that I posted.

I want to know what makes these thrive. I want to duplicate it as much as I can. Some day, I will have solar tubes with some supplements, but my current house does not allow it. I don't care about all of the other posts and stuff in this thread. Those acropora GROW out of the water and thrive.

Cool. Where was that?
I stand behind my point though - most corals in the trade do not come from the exposed areas and it isn’t a good talking point.

oreo54 · Mar 3, 2023

There is no argument that the amount of solar " food" is highest the closer to the surface.
And there are 100's of interacting species both micro and macro absorbing and releasing who knows what.

But there is no doubt in my mind when those corals are exposed they are not " thriving" but surviving at that time.
And their survival can be on a knife edge.

After submersion in shallow water, high ppfd, plenty of other organisms growing, pooping, dying provided a rich biome.
Yes they developed coping mechanisms such as heavy slime coats, thick tissue layers , production or adsorption of maa's, and probably a few other factors that makes them survivors.
They have evolved to survive the stress and thrive when it is lessened.
They have also evolved to change to their environment.

Who knows what they lose after being captive grown and/or bred.

Those reef flats you show..how long are they exposed daily( seasonally?).
What time of day?
All the little bits one may not see over the macro-viewpoint.

Damage varies by a host of intersecting factors such as waves, water temp, solar elevation, UV exposure, ect.

The way I see it is if you can't match the growth rate after removing their stress period, it may be some other factor than light which you can, normally, give in adequate amounts.

One thing you normally don't do is the daily bell curve delivery of par.
I would not discount this as a factor.

Correlation does not infer causation .
The growth rate could be from any number of causes.

You only collected the coral, not the environment ...
You may not know what you don't know..

And, at times, ignore contrary facts.

One of my projects involved the determination of light required by photosynthetic corals (note: required versus tolerated.)

The take home message is this: These Porites corals living in waters only a few centimeters deep required only a fraction of the light intensity they will experience. Their zooxanthellae will be at a maximum rate of photosynthesis early in the morning, and their natural protective devices (the Xanthophyll Cycle) comes into play during mid-morning and protects them until light intensity drops in the late afternoon (assuming it is sunny all day.)

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In addition, some corals (such as Acropora cervicornis) are known to host different Symbiodinium species throughout the year – zooxanthellae with tolerance of higher light (and heat) tolerances can be prevalent during the summer months.

Could be after time the species of Symbiodinium changes..

I don't doubt you saw what you saw, I doubt the thing you think is the cause.
Could be a micro nutrient, could be a symbiotic bacteria that doesn't travel well, could be........ ect.

That all said "I" don't have an answer and apparently others either..

JUST food for thought.

areefer01 · Mar 3, 2023

Thales said:
Shallow corals that get exposed are adapted to that environment, and that environment is often a war zone. Most of the corals we keep do not come from the areas that get exposed. I don’t think such corals are a good talking point for this kind of discussion.

Great point. I don't know the percentage but one could argue most of the corals we are buying today are a few generations removed from the wild.

A. grandis · Mar 3, 2023

Thales said:
Cool. Where was that?
I stand behind my point though - most corals in the trade do not come from the exposed areas and it isn’t a good talking point.

And why then are we even here discussing about UV? LOL!!! We all know that UV isn't necessary to grow corals. LOL!
That would be the ONLY reason why we would have a UV thread open, right? LOL! I mean, for those who care about having the UV in the spectrum.
We've been discussing and trying to understand why metal halides is what it is in comparison to LEDs for at least more than a decade here. It comes down to personal preferences in that regard, period!
Everyone has the right to use what they want!
This thread is nice and colorful, but all here have known all this for years. LOL!
Bottom line is that no one can explain scientifically to the core why metal halide is the KING of lights, besides what we have already publish here.
All the qualities and explanations I left here before sums what we know.
If this was opened to discuss about that video it should be addressed in the title.
Is this a thread to prove that corals don't need UVR to grow, using LEDs?
Done, now they can close. LOL!

One thing I know... there are a lot of people changing to metal halides lately! Personal preferences...

I've been saying this forever here... Iwasaki was the very best artificial light of all that I've tried! But all the other halides will follow that path too!
Again... for those who want to know the best light for corals and sun replication, independently of any excuse! This is from a guy who used all LEDs available in this hobby! (mic drop!)

It always ends up in the same.
This is probably the end of this thread?
Have fun with you reefs.

Hurricane Aquatics · Mar 4, 2023

Wow, I missed all the fun! .

My thoughts, Metal Halide 100% offers much better health, growth, and overall ease of keeping corals. You can make a couple of mistakes and get away with it using metal Halide.

LED seems to be the king of adding color through the blue LEDs.

I recently added 2 Illumagic Blaze X 90 36" 235w LED fixtures to my Reef Brite 250w MH. It made the corals much happier and my color is looking great.

LED have definitely improved, but the days of BRS touting "spectrum is everything" is ridiculous. People also say LUX doesn't matter, but I disagree. MH is two or three times as bright as LED. All these have to be taken into consideration if we ever want to find out why one technology works over the other.

Thales · Mar 4, 2023

A. grandis said:
And why then are we even here discussing about UV? LOL!!! We all know that UV isn't necessary to grow corals. LOL!
That would be the ONLY reason why we would have a UV thread open, right? LOL! I mean, for those who care about having the UV in the spectrum.
We've been discussing and trying to understand why metal halides is what it is in comparison to LEDs for at least more than a decade here. It comes down to personal preferences in that regard, period!
Everyone has the right to use what they want!
This thread is nice and colorful, but all here have known all this for years. LOL!
Bottom line is that no one can explain scientifically to the core why metal halide is the KING of lights, besides what we have already publish here.
All the qualities and explanations I left here before sums what we know.
If this was opened to discuss about that video it should be addressed in the title.
Is this a thread to prove that corals don't need UVR to grow, using LEDs?
Done, now they can close. LOL!

One thing I know... there are a lot of people changing to metal halides lately! Personal preferences...

I've been saying this forever here... Iwasaki was the very best artificial light of all that I've tried! But all the other halides will follow that path too!
Again... for those who want to know the best light for corals and sun replication, independently of any excuse! This is from a guy who used all LEDs available in this hobby! (mic drop!)

It always ends up in the same.
This is probably the end of this thread?
Have fun with you reefs.

I don't understand what that has to do with what I wrote.

Thales · Mar 4, 2023

A. grandis said:
Again... for those who want to know the best light for corals and sun replication, independently of any excuse! This is from a guy who used all LEDs available in this hobby! (mic drop!)

I don't think this is the mic drop you think it is.

"
0:45

unequivocally it would be
0:47
uh
0:49
250 watt iwasaki metal halides in a
0:53
giant reflector there you go yeah metal
0:56
halides start
0:58
with pulse start i mean if no other
1:02
consideration for power
1:04
heat
1:05
you know size over the aquariums
1:07
controllability is we're talking about
1:08
sheer
1:09
sun replication iwasaki 65k you know uh
1:13
pulse dart ballast with a giant
1:15
reflector i um with a ring of like blue
1:19
and royal blue leds just magically built
1:21
into the reflector to you know give it a
1:23
little blue spice to it unequivocally
1:26
yeah that would be the one if there's
1:28
like no holds barred for sure but with
1:30
cost of running them and acquiring the
1:32
bulbs and the size and the heat um
1:35
obviously that's not the first choice"

There is more in the middle, but at the end -

"but
4:54
to be honest you use
4:56
refleds radions hydras it's it's how you
4:59
use them man it's like
5:01
we shouldn't have this conversation
5:02
about like uh f1 race cars it's like
5:04
what race car is going to win the race
5:06
it's not that it's the driver"