UV spectrum for corals

[FBAA]

Does anyone realize a PAR meter measures terrestrial plant spectrum and doesn't realize the benefits of the amount of UV available to corals. Bacteriochlorophylls are outside of the par spectrum. Is high energy UV required for corals to grow.

 

[vetteguy53081]

Yes but it is measured in a different way as many coral require a photosynthesis for product of zooxanthelle- their food sources. You’re referring to OAR meter. In the hobby, we use a LUX meter referred to as PAR meter.
Lux’ is an internationally accepted measure of light intensity. Lux meters do not ‘see’ blue and red light very well, and it is these wavelengths that are most responsible for promoting photosynthesis. They are designed to report light intensity to which the human eye is most sensitive (green light). Maximum lux is about 120,000 (in the tropics at noon on a cloudless day (many lux meters will report lux up to 50,000, making them adequate for many reef aquaria.
In reefing, we use lux meters for measuring light and although these are better than not taking measurements at all, the preferred method is using a quantum meter which converts LUX to PAR.

 

[FBAA]

Yes, all very true but does the meter include UV for bacteriochlorophyll. Most meters don't measure in the UV range.

 

[BCSreef]

Depends on the meter. I think most if not all hobbyist-grade Light meters do not measure true UV or even near UV.

 

[mdb_talon]

Yes it is an "issue" that has been discussed for many years. Boils down to PAR meters can be very beneficial, but of course they are far from perfect(at least the ones we would commonly be using).

Until fairly recently though i would say few cared about UV other than shielding it(as needed with metal halides), but seems the last several years more acceptance that coral really does benefit from some UV. Something we always got to some extent with metal halides(shielding was not perfect), but with the initial wave of LEDs it was rarely included. Now it seems even discount led fixtures are including at least some UV spectrum though.

 

[FBAA]

I'm just getting tired of the bacteria in our corals being compared to terrestrial plants. They are far from that and their are are far more photoreceptors available to help them grow. That includes high energy UV that current units don't measure.

 

[FBAA]

Has anyone seen any recent oceanic spectrum data taken over a reef. I'd like to get it incorporated in my calculator for LED design.

 

[BCSreef]

Try Dana Riddle on the Lighting forum for spectral data on reefs. He has done quite a bit of research out on the reefs.

 

[FBAA]

Will do - Thank you.

 

[oreo54]

Has anyone seen any recent oceanic spectrum data taken over a reef. I'd like to get it incorporated in my calculator for LED design.

Pretty sure Dana has that..and I'm sure I saw it but.....
Just an article related to your quest..
https://reefs.com/magazine/photosyn...results-of-short-term-exposure-to-led-lights/

The "need" for UV is debateable..

Optical Absorption of Water Compendium

 

[FBAA]

My current build of the LED lights is configured using the calculated attenuance and ratios for 3M depth in clear seawater. The LED wavelengths are shown. The initial version didn't have a solid fill for LED spectrum but worked well. LED's have a very tight peak so spacing the various wavelengths as close together as possible to get the overlap interference is needed especially for UV LED's.

 

[oreo54]

My current build of the LED lights is configured using the calculated attenuance and ratios for 3M depth in clear seawater. The LED wavelengths are shown. The initial version didn't have a solid fill for LED spectrum but worked well. LED's have a very tight peak so spacing the various wavelengths as close together as possible to get the overlap interference is needed especially for UV LED's.

Custom Popbloom?

 

[FBAA]

Yes. for some reason these lights are popping up in multiple threads today. I had a knee replacement so I don't move much so I'm messing with new spectrum combinations. Here is the light I'm putting together now.

 

[oreo54]

Yes. for some reason these lights are popping up in multiple threads today. I had a knee replacement so I don't move much so I'm messing with new spectrum combinations. Here is the light I'm putting together now.

Ignoring UV and IR for the moment..
Base structure of "3m" ish led array..well closer to 5 and dampening the "yellow".

• LED UV (410nm) [120°] x20
• LED Violet (430nm) [120°] x15
• LED RoyalBlue (440nm) [120°] x20
• LED Blue (460nm) [120°] x25
• LED Blue (470nm) [120°] x20
• LED Cyan (490nm) [120°] x72
• LED Cyan (510nm) [120°] x50
• LED Green (520nm) [120°] x30
• LED Green (540nm) [120°] x40
• LED Amber (580nm) [120°] x30
• LED Red (610nm) [120°] x3
• LED Red (630nm) [120°] x3
• LED CoolWhite (8000K) [120°] x30

Granted more "windex blue" than many find acceptable..
But that is nature for you.
Note the large addition of cyans and greens..
I used so many diodes to equal sunlight curve.

SPECTRA

SPECTRA can perform the optical simulation of many required for coral breeding. SPECTRAはサンゴ飼育に必要な多くの光学シミュレーションを行う事が可能です。

spectra.1023world.net

Just more of an fyi..

violet pump plus RGB phosphors Believe the left peak is the pump @410-420:

Life would be soo much easier w/ violet plus phosphor reef centric diodes..

 

[FBAA]

I do have a spectrometer here somewhere. Yes the LED classification (Bins) can be pretty loose. Unfortunately the UV LED's don't use a fluorescent coating to spread out the peaks. I have LED's Binned every 10nm between 365 and 470nm. That's about the best coverage I can find right now.

 

[oreo54]

I do have a spectrometer here somewhere. Yes the LED classification (Bins) can be pretty loose. Unfortunately the UV LED's don't use a fluorescent coating to spread out the peaks. I have LED's Binned every 10nm between 365 and 470nm. That's about the best coverage I can find right now.

Sorry.. 1/2 of my above response got lost..
No matter wasn't critical..
Just some links.

Lighting the Aquarium Part 7-Photosynthetically Usable Radiation •Orphek

Lighting the Aquarium Part 7: Photosynthetically Usable Radiation By Dana RiddlePhotosynthetically Usable Radiation (PUR) is a portion of the spectrum...

orphek.com

you certainly have the right idea though.

 

[blasterman]

There is zero evidence that light below 450nm has any benefit to corals. It's just bantering points pushed by people who are having trouble growing coral and picking a straw horse to blame.

UV LEDs only started showing up in fixtures when the semi conductor industry figured out how to make them reliable and cheap.. The primary market for these things is DJ lights ...not reef lights. I have a bunch of 50watt 395nm chips. They have no business on my reef tank.

The Spectrum of the sun is pretty well known and doesn't have to tested. The spectral absorption of chlorophyll is also well known. The spectral band for Clorophyll photon absorption is also pretty wide. Zooanthalae algae in corals can pretty much thrive when being hit with photons from 420nm to Windex. Higher energy , higher frequency photons with shorter wavelengths dont translate into a higher conversion efficiency for chlorophyll. As long as its blue light of any flavor it works for Zooanthalae.

Reef Halides lack violet and UVA - no problem growing coral.

Reproducing the spectrum of the sun, providing you could actually do so which is unlikely in 3m of water won't grow corals better. Zooanthalae will just absorb the same blue photons as they normally do and ignore the rest.

Put a plasma sulfur above your tank if you want to truly mimmick solar spectrum. It won't grow corals better than a black box at the same PAR.

 

[monkeyCmonkeyDo]

Corals adapt and evolve just like we do. Just not as fast at adapting. Why sps coral browns and bleaches.
Remember we all have diffrent lights. In the wild its just the 1 big great sun around the world.
D

 

[FBAA]

There is zero evidence that light below 450nm has any benefit to corals. It's just bantering points pushed by people who are having trouble growing coral and picking a straw horse to blame.

UV LEDs only started showing up in fixtures when the semi conductor industry figured out how to make them reliable and cheap.. The primary market for these things is DJ lights ...not reef lights. I have a bunch of 50watt 395nm chips. They have no business on my reef tank.

The Spectrum of the sun is pretty well known and doesn't have to tested. The spectral absorption of chlorophyll is also well known. The spectral band for Clorophyll photon absorption is also pretty wide. Zooanthalae algae in corals can pretty much thrive when being hit with photons from 420nm to Windex. Higher energy , higher frequency photons with shorter wavelengths dont translate into a higher conversion efficiency for chlorophyll. As long as its blue light of any flavor it works for Zooanthalae.

Reef Halides lack violet and UVA - no problem growing coral.

Reproducing the spectrum of the sun, providing you could actually do so which is unlikely in 3m of water won't grow corals better. Zooanthalae will just absorb the same blue photons as they normally do and ignore the rest.

Put a plasma sulfur above your tank if you want to truly mimmick solar spectrum. It won't grow corals better than a black box at the same PAR.

I am going to assume you meant 350nm not 450nm. Metal halides did have a fairly solid UVA spectrum down to 350nm

Light adaptation of corals Part 2 | Coral Reef Magazine

Light adaptation of corals. Spectral diffusion of light.

www.coralreefmagazine.com

I am also interested in seeing what if any accessory pigments and bacteriochlorophylls are active and if they actually matter when it comes to corals. A- they extend into the UV range, B- they have had a longer time to evolve.

See attached.

 

[oreo54]

Playing With Poison – Ultraviolet Radiation

This article documents the results of an experiment designed to examine the effects of artificially-produced UVR on symbiotic zooxanthellae. We'll also examine inexpensive ways to test your system and, if necessary, corrective measures one can take.

reefs.com