LED’s- No UV? Do corals need UV for longterm health?

[ClownWrangler]

Well, even if the UV LEDs don't offer much in terms of added benefit for coral growth, having as many different colors as possible in the actinic and UV range does bring out the colors in the corals better. I noticed shorter wavelength tend to bring out the green and red colors more and longer wavelengths bring out orange better.

Also, the green pigment in corals and anemones is like the pigment in our skin in that it blocks UV, so its possible some people whose BTAs turns from green to brown, it is not getting enough UV. Perhaps they just need to get a tan. Just a theory. I have also been wondering if UV helps BTAs fight off bacteria.

This is a nem under 395nm vs 470nm. As you can see, the 395nm brings out the green better.



This is gracilaria macro algae. The UV makes red macro algae deep red. The Blue sort of washes out the color.

 

[outhouse]

The lights that I know of that have true UV are:

GHL Mitras (385nm)
Orphek Atlantik & OR3 (390nm)
Kessil (390nm (I Think))
Gieseman Futura S (390nm)
Maxspect Jump series (390nm)

Add luminbar V2 from reefbreeders

 

[outhouse]

I have had only a little 420 spectrum on my BTAs and they have been bright green.

 

[JNalley]

Add luminbar V2 from reefbreeders

K, just the
Blue/UV Hybrid- A balanced mix of 430nm violet, 450nm Royal Blue, 380nm UV, and 480nm Cool Blue. Great mix of color pop and brightness.

HO (High Octane) UV– Mix of 430nm, 410nm, 405nm violet, and 380nm UV- guaranteed to make your SPS corals happy

have them and they're 380's. I'll add them to my list. Thanks for that.

 

[outhouse]

K, just the
Blue/UV Hybrid- A balanced mix of 430nm violet, 450nm Royal Blue, 380nm UV, and 480nm Cool Blue. Great mix of color pop and brightness.

HO (High Octane) UV– Mix of 430nm, 410nm, 405nm violet, and 380nm UV- guaranteed to make your SPS corals happy

have them and they're 380's. I'll add them to my list. Thanks for that.

Looks like their V1. Specs

 

[outhouse]

385. 405. 430

 

[JNalley]

Looks like their V1. Specs

yeh, I dunno, I went here: https://reefbreeders.com/product-category/lumenbar-color/ and didn't see anything labeled V2, so I just copied what was from those. Whether they're 380 or 385 those are the only ones below 400 which makes them the only True UV's. It's also hard to gauge how many there are per strip since they don't give that info (would have to buy them to count)... GHL employs 1 385nm chip per puck, and on the 7204's there are 4 pucks, and the 7206's have 6. I'm trying to map out how many LED's in True UV each one employs as well as a part of my data.

 

[Dana Riddle]

Dana, what data made you change your mind from what you measured in that video with the Hawaiian Porites in the tide pool. Did you measure other stony corals?

I still think there’s some truth to that statement you made! Are we slowing down these corals with too much PAR?!?

“What does it tell us about the amount of light required by the captive dinoflagellates when their host generates protective colorful proteins in order to protect itself from harmful by-products of photosynthesis (such as hydrogen peroxide)? Acropora specimens, as a general rule, are thought of as ‘light-loving’ by many hobbyists. Does this concept hold water when the coral produces protective pigments at light levels of, say, 200 µmol·m²·sec?”

It has been known for quite some time that chlorophylls can absorb light well into the UV range, but phycology engineers decided to use plastics in PAR sensors that have a cutoff at 400nm. It doesn't change the photosaturation points when using an older PAR sensor, but the newer ePAR meters can give us a better understanding of zoox photosynthesis.

 

[outhouse]

yeh, I dunno, I went here: https://reefbreeders.com/product-category/lumenbar-color/ and didn't see anything labeled V2, so I just copied what was from those. Whether they're 380 or 385 those are the only ones below 400 which makes them the only True UV's. It's also hard to gauge how many there are per strip since they don't give that info (would have to buy them to count)... GHL employs 1 385nm chip per puck, and on the 7204's there are 4 pucks, and the 7206's have 6. I'm trying to map out how many LED's in True UV each one employs as well as a part of my data.

BRS. Has all the new Info

 

[JNalley]

It has been known for quite some time that chlorophylls can absorb light well into the UV range, but phycology engineers decided to use plastics in PAR sensors that have a cutoff at 400nm. It doesn't change the photosaturation points when using an older PAR sensor, but the newer ePAR meters can give us a better understanding of zoox photosynthesis.

Hey Dana, I Just checked out Apogee's website, and the ePar meters listed on the site show a spectral range of 400-750 instead of 400-720, which means it extends into the IR range, but doesn't look like it drops back into the UV range. Is this the same PAR meter you're talking about? or is there a new, not yet released one, that expects to dip into UV?Z

Quantum (PAR & ePAR) Sensors / Meters - ePAR Sensors - Apogee Instruments, Inc.

www.apogeeinstruments.com

 

[Dana Riddle]

Hey Dana, I Just checked out Apogee's website, and the ePar meters listed on the site show a spectral range of 400-750 instead of 400-720, which means it extends into the IR range, but doesn't look like it drops back into the UV range. Is this the same PAR meter you're talking about? or is there a new, not yet released one, that expects to dip into UV?Z

Quantum (PAR & ePAR) Sensors / Meters - ePAR Sensors - Apogee Instruments, Inc.

www.apogeeinstruments.com

For the life of me. I can't explain why Apogee doesn't advertise the ePAR sensor 'sees' radiation down to 380nm. I'll get in touch with Chris Madsen at Apogee and see what he has to say. I think Apogee is doing themselves a disservice.

 

[J1a]

I have managed to aquire a spectral photometer with submersible fiber optic cable. The device is calibrated for seawater applications. I have taken a quick measurement of my aquarium.

Two data points shown below.

Just under the surface of water

Near the bottom of the 2.5 ft deep tank.

Seems that UV is there, but in very limited quantities. It also seems that UV gets scattered/absorbed faster than other wavelengths.

 

[telegraham]

Yes, those were the only two he knew of (he mentioned as much when he did the Mitras review) however, the others have been confirmed by me while researching lights. They have advertised nm LEDs from known LED manufacturers (OSRAM and CREE) who do make those nanometers, there's no reason to lie about it (and doing so would result in false advertising and lawsuits).

Not a well actually, but there are others I've personally measured, like the Red Sea 90, that have UV. In this case, a 385nm bump. I mentioned GHL and Kessil because I know they appropriately advertise UV.

 

[telegraham]

How do you perform a surface agitation spectrum drift test without water?

That test is so flawed that it should be disregarded. I one performs the same test dry, and in many cases, you'll see the same drift (dynamic spectrum). More often than not, the spectrometer is seeing the PWM dimming of different channels. The colors are simply cycling at different frequencies. I've tested the same lights with the same spectrometer.

 

[J1a]

That test is so flawed that it should be disregarded. I one performs the same test dry, and in many cases, you'll see the same drift (dynamic spectrum). More often than not, the spectrometer is seeing the PWM dimming of different channels. The colors are simply cycling at different frequencies. I've tested the same lights with the same spectrometer.

One possible approach is for the spectrometer to take an integral over a short period of time. Say, 10 minutes. That's definitely achievable and will account for the effect of surface agitation.

 

[J1a]

Imo testing the spectrum wet vs dry does have some significant impact due to refraction and reflection at the surface. No matter how wide/even the spread of light is, a lot of rays are going to strike the surface of water in a fairly oblique angle. This would cause a fair bit of par/spectrum change.

 

[telegraham]

I just can’t understand why EcoTech would call it UV if it’s 405nm. Makes no sense to me. Wouldn’t some of these lighting guru’s call them out on that? How are we just now hearing about this? Did the G4’s have a UV channel too?

The Radion, Sky, and ViparSpectra (along with so many others) all ramp to a 400-405nm violet. The amount of legit UV is that within the highlighted box (Gen 5 Blue shown). Although technically UV generating, the diode is violet. Others, like GHL and Kessil, have UV diodes with peaks below 400nm.

Things you'll hear is that UV diodes burn out over time, so manufacturers avoid them. You may also hear that UV is marketing. I don't consider either to be accurate. Proper engineering and design choices, yes. Although not required, UV plays a part in coral coloration. Nearly identical PAR with corals in the same water, and I've have Disneys color up differently. Neither was better, but the color difference was notable.

Then there's the bacterial suppression idea recently floated by Mike Paletta within the context of MH vs LED. Lab testing suggests that UVA can have anti-bacterial effects. That's something worth considering, and given the testing provided by Aquabiomics, it's worth pursuing to satisfy my curiosity.

 

[telegraham]

Imo testing the spectrum wet vs dry does have some significant impact due to refraction and reflection at the surface. No matter how wide/even the spread of light is, a lot of rays are going to strike the surface of water in a fairly oblique angle. This would cause a fair bit of par/spectrum change.

Have data? Would love to see that spectrum impact quantified. If within the context of PAR, I totally agree. A wet, clean, and empty glass box will always produce better PAR numbers that may not represent many reefers' systems.

 

[J1a]

Have data? Would love to see that spectrum impact quantified. If within the context of PAR, I totally agree. A wet, clean, and empty glass box will always produce better PAR numbers that may not represent many reefers' systems.

Yes. I have done non-rigorous test just to see what kind of potential impact could be.

A bit of the context. My set up has 4 units of LED (240 W each). The red blobs in the diagram below represent the lights, while the x represents the position where the readings are taken.

The reading are taken with the probe just above, and just below the water surface.

Here is the data.

The difference in Par is fairly significant. Spectrum difference, on the other hand, seems to be there (by taking the ratio of the aggregate RGB groups 0.86:0.82:0.63). I think I will have to repeat the measurement, and export out the raw data to make better comparison.

 

[J1a]

The Radion, Sky, and ViparSpectra (along with so many others) all ramp to a 400-405nm violet. The amount of legit UV is that within the highlighted box (Gen 5 Blue shown). Although technically UV generating, the diode is violet. Others, like GHL and Kessil, have UV diodes with peaks below 400nm.

I think an important factor to consider is the amount of the UV leds. I would think most light sets place a lot of emphasis on the 450nm range, do they still provide enough diodes to supply meaningful amount of UV?

I guess have a token 3-4 true UV diodes probably won't make much impact.