PAR, LEDs, and T5/MH. I'm confused.

[jda]

That is my point exactly... leave photons or any reference to light is light out of it. It is way more complicated than that.

I hope that nobody thought that I had any answers to all of this. Just trying to illustrate that laziness of the argument.

 

[oreo54]

My point is, and it may have an answer.. what makes this err "special"?

Spectral Analysis Of 400w Lamps: XM, Radium, Osram And Sunmaster, PFO

Sanjay and Tim update our readers on the spectral output of these bulbs along with thoughts on each.

reefs.com

For fun..History.

http://reefkeeping.com/issues/2007-04/jb/index.php

 

[jda]

I am sure that it has an answer, but we don't know what it is... at least not 100% of what it is... or even 10%, most likely. You can bet that it is not just that line, since it only represents a small amount of specialness (is that a word?) but us simple minded humans often don't look further than that.

Being a realist, I mostly do not care since results and experience are my thing, but it is fun to ponder and sometimes fun to talk and post about.

 

[oreo54]

Maybe it is the "heat" (850 and above).
See little of anything else that can make much of a difference..
Daylight salted metal halide.
Double the temp 10x increase in a chemical reaction..
Like deep tissue massage..

Thing about "results" as you are well aware is the wanted result isn't a universal.
One could test it by an out of the box experiment involving LED's and heat lamps..
Orphek did add 850's -ish, personally thought it was weird but ?????
Maybe up the volume..

 

[jda]

I think that I have told you this before, but we put 20k Radium and 14k Phoenix in a integrating sphere with a several-hundred-thousand dollar spectrometer attached. 2-3 of the output from 14k phoenix was over 850nm. The line went well over 20k nm, but it was not much. The radium had more like 4-5%, IIRC, maybe 3-4%, but more... which is why it heats up the tank more. I would like to try out the new Hamilton 20k bulb since it does not put off as much heat, but I live 800 miles from there now. I don't know what this means, only that this is what we found.

I wonder if massaging coral would help? I do find competent flow to help, but way too much to hurt... probably like pressure of a massage.

I do find it funny how most of the time wanted results are more universal than the are not.

 

[djf91]

jda, are you still living in Missouri?

 

[jda]

Nope. Moved to Colorado a while back.

 

[djf91]

Dang, jealous of that. Dave (Nanook) had mentioned you do or did live here in Mo.

 

[fishmonkey]

PAR is an inherently difficult measurement to work with because it weights each spectrum of light differently - more weight is put on the green to red portion of the spectrum. Simply put, a single photon of red light will register nearly 2x as high as a single photon of blue light. It's also why the PAR at the surface of a coral reef is close to 2000 PAR - there's a whole lot of light that the coral aren't using.

Just for fun, we put out 600 PAR using all green light on one of our stage lighting fixtures - but it wouldn't grow a single piece of coral because the coral don't need green, they need blue (specifically 425nm and 455nm for photosynthesis).

The other major thing to consider is that coral are remarkably resilient and adaptable organisms. You may have a piece of coral at 100 PAR that someone else has at 300 PAR. Both can grow and look amazing. Slow is always better when changing things.

To your question about treating corals different based on where they are - that depends on your light. A good LED will blend the spectrum together and have it be even across the entire tank (that's why we do our lights the way we do - the spectrum is mixed immediately). If you're working with a very spread out LED light source, you're more at risk of having a "fractured" spectrum - where there may be enough PAR, but you're missing a critical wavelength.

Lastly - whites and blues are different across each brand. On a Kessil light, Kessil Logic keeps the spectral output the same regardless of how white or blue you choose to make it. Other brands have similar features, while some do not.

Let us know if you've got any other questions about light - we'll help how we can. We've been doing fiber optic switches since 1986, and LED lights since 2002, so we know a thing or two about photons

im actually running 2 gooseneck kessil tuna blue a160 on my 40 gallon breeder and starting to think its not the lighting thats bleaching my monti cap. my assumption is that a quick change in lowering par would not cause bleaching.

 

[fishmonkey]

They probably would have grown if you gave them 300 PAR of green. There are plenty of proteins that can do photosynthesis in the green range, even if it is not as efficient. Proteins don't just respond in those two wavelengths - a few are optimal there, but not all and most excite from a wide range of wavelengths. This is fake news and one of the reasons that people get so confused with light.

PAR meters do not weigh wavelengths, as posted above. It is one of the downsides to the tool, along with not capturing wavelengths below 400nm or above 700nm. They also have no opinion on spectrum and an overabundance in one area can drive the number up, but be harmful, or not helpful, to actual corals. However, they can still be useful as a guideline or swag. They are even more helpful if you are fairly certain that your spectrum is at least decent.

What you really need to know is that too much PAR from nearly all LEDs can burn coral. Twice or thrice this amount, or more, from mercury sources does not. Even more than this from the sun or solar tubes does not. There are lots of theories why, but the phenonomen is real in our tanks. I mostly deal in Acropora and while there are a few who can grow acros above 350-400 PAR of LED, the majority cannot - acropora can handle 1200 PAR from my MH. They can do sunlight in a shallow pool well over 2000. I even grow bounce, eclectus, jawbreaker mushrooms and RBTAs (Colorado sunbursts) in 750 PAR under MH in shallow frag tanks and they grow fast and thrive. They might not need it, but the increase in growth is there if you give them a lot of quality light. They would all likely shrivel and die with 750 PAR of most any LED.

What Bpb was referring to in post #3 is the Emerson effect. It moves energy from Photosystem II to Photosystem I with the help of IR light. This is one theory as to why mercury bulbs can give much more PAR to corals without burning them. ...just a theory. There is a lot of info out there if you want read up on it.

Just go slow and watch your corals. If they don't expand as much after a bump in intensity, then back it off. They will tell you what you need to know if you give them time to react and pay attention.

regarding wavelengths is it safer to just run blue lights from now on? i read that corals love white lights but now im afraid that maybe its burning them.

and its hard to tell how my monti cap is doing other than the bleaching which is really just it slowly deteriorating.

 

[fishmonkey]

The other two also keep near NSW parameters with more natural levels of N, P, carbonate, etc. - I am sure that you have heard my theory that the higher levels of N and P which slow down cellular function along with LED is a bad combo, but this has not been substantiated beyond just a theory.

i do have higher nitrates and im thinking that has to do with my problems. mainly the sps. its either that, flow or lighting from what i can think of

 

[Nonya]

So after renting a PAR meter and finding out my intensity was way too low I figured I should slowly acclimate my coral to 10% a week higher intensity lighting. My corals were surviving at these super low levels but not really growing all that much. It's been about 5 days since and I've noticed some of my coral doing better and some not as much. This may be due to other factors but that's beside the point.

From reading what's on the forums here about PAR, I found out LEDs can burn coral easier than other lighting and am wondering a few things.

Should lower PAR levels should be considered when using LEDs? (Tidal Gardens vs. Vivid Aquariums PAR)
Is there a PUR to PAR ratio to consider when using LEDs vs T5?
Should corals put directly under a LED light source be treated differently despite PAR?
How should whites and blues be treated on LEDs?

Part of the answer may come from knowing which specific PAR meter was used. Some underestimate PAR in the blue-violet region, which is the high energy region.

 

[Nonya]

Can you list which corals are having issues, chemistry stats, and PAR readings you took at their specific locations?
Since you're using a 40 gallon aquarium, there could also be other possible causes: nutrients, pH, alkalinity, flow, types of coral.

 

[fishmonkey]

Can you list which corals are having issues, chemistry stats, and PAR readings you took at their specific locations?
Since you're using a 40 gallon aquarium, there could also be other possible causes: nutrients, pH, alkalinity, flow, types of coral.

It’s been a while since I posted on this thread. Since then I raised my lights to around 7 1/2 inches from surface of water, added ph probe, and started dosing kalk. Things are going better now.

 

[Nonya]

Just for fun, we put out 600 PAR using all green light on one of our stage lighting fixtures - but it wouldn't grow a single piece of coral because the coral don't need green, they need blue (specifically 425nm and 455nm for photosynthesis).

Just those two wavelengths? That seems a bit overly simplified. What studies resulted in that assessment?

 

[Nonya]

It’s been a while since I posted on this thread. Since then I raised my lights to around 7 1/2 inches from surface of water, added ph probe, and started dosing kalk. Things are going better now.

Awesome!

 

[oreo54]

Just those two wavelengths? That seems a bit overly simplified. What studies resulted in that assessment?

They are just using the Chl a and c absorption peaks probably.

Figure 6. Absorption spectra of the five zooxanthellae pigments in...

Download scientific diagram | Absorption spectra of the five zooxanthellae pigments in respect to both spectral datasets: the QB2 visible dataset (blue, green and red) and the WV2 visible dataset (“coastal”, blue, green, yellow and red) (modified from [41]). from publication: Enhancing Coral...

www.researchgate.net

One thing though peak changes by solvent in vitro and can differ from in vivo as well.
Shifts a bit..

 

[Nonya]

They are just using the Chl a and c absorption peaks probably.

Figure 6. Absorption spectra of the five zooxanthellae pigments in...

Download scientific diagram | Absorption spectra of the five zooxanthellae pigments in respect to both spectral datasets: the QB2 visible dataset (blue, green and red) and the WV2 visible dataset (“coastal”, blue, green, yellow and red) (modified from [41]). from publication: Enhancing Coral...

www.researchgate.net

One thing though peak changes by solvent in vitro and can differ from in vivo as well.
Shifts a bit..

Absorption peaks don't necessarily translate to needing only those two wavelengths for photosynthesis. There's also the action spectrum for photosynthesis, which shows a full spectrum of light wavelengths that actually result in photosynthesis.