T5 Photosynthetically Usable Radiation (PUR) Ratings

[jda]

I understand what Kirk said... however, am I supposed to believe that a protein/clade that has developed to absorb UV light will waste any of it? I totally believe that a protein that will work with red might reject the excess light (and probably produce color with the excess), but I just don't buy it with the proteins that thrive in the lower nm range with higher energy. ...anyway, just something to consider that when given time to evolve that nature is less prone to not waste energy than otherwise.

I just want to get on the record that using Seneye or Orphek's verions of PUR could be harmful. If manufacturers start to use this as a target to get the "efficiency" up to sell units, then what happens if they are wrong (and they probably are since we are truly just guessing at most of this) and people buy stuff that is worse than what they had on a promise that it was better? I reserve the right to change my mind when I learn more...

 

[oreo54]

I understand what Kirk said... however, am I supposed to believe that a protein/clade that has developed to absorb UV light will waste any of it?

https://www.advancedaquarist.com/2006/9/aafeature
any that absorb @<400nm and re-emit as florescence is "waste" to the emittee... but possible advantage to it's neighbor..

UV is complicated since, generally speaking, the lower the wavelength the higher the damage/benefit ratio gets..

Past studies have found that the calcium carbonate exoskeletons of corals that make up reefs fluoresce under ultraviolet light, suggesting that they absorb UV rays. To see if this material protects the organisms that live on reefs, marine biologist Ruth Reef of the University of Queensland in Australia and colleagues studied sea anemones (Aiptasia pulchella). These relatives of corals have similar tissues and are also home to symbiotic photosynthetic algae.

The team placed the anemones on top of either coral skeletons or white plumbing tape in the lab. Unlike the tape, the skeletons absorbed nearly all the harmful UV rays, emitting it as yellow fluorescent light, the researchers reported 25 November online in PLoS ONE. What's more, anemones placed on the coral received four times less UV radiation and showed about seven times less damage to their DNA than those placed on the tape. The team saw this effect even when they ground the skeletons into a fine powder, suggesting that the protection is due to the chemistry of the coral exoskeleton, not to the scattering of UV rays from its rough, complex surface.

not being "absorbed" by photosynthesis..

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776492/

OF COURSE the biggest thing is.. "which wavelength are you referring to"

 

[jda]

Again, I have no doubt that that energy does not matter for some proteins, but I just cannot believe that is true for all of them. Look at some of the ones in that articles where the excitation and emission range is nearly 100nm - this is a large use of energy and most of these excite under 400nm - when compared to some higher in the range that only have a range near 10. This tells me that different proteins can use more or less energy than others. I know that fluorescence (the purpose of that article) is not the same as photosynthesis, but they are also not completely divorced.

When I talk about UV, I nearly always mean 350-400nm... the part that will penetrate water below a few inches (to a few meters) and will get outside of a MH or Flourescent tube over our tanks. (I know that there is a trace below 350nm for some mercury-based bulbs) I have seen the damage that UVB can do to corals and fish when people chose not use the glass on their DE bulbs. So far, I have not seen anybody use an arc welder above their tanks, so I have no observations on UVC.

 

[naoki]

I'm still unpacking lab gear and found some T5 lamps. As a lark, I checked PUR with the Seneye device and found a cool white to rate at 60% and an actinic at 82%. If Photosynthetic Photon Flux Density (or PAR, if you will) are the same, we can develop a hypothesis that the actinic lamps are 22% more efficient. The most efficient LED I've seen is in an Orphek Atlantik luminaire and it rated 87%.

I don't think PPFD is similar between cool white and actinic. I haven't mesaured PPFD of actinic, but when I compared the purple plant grow bulb and 6400K white T5HO, they were quite different (81 micromol/m^2/s for Odyssea plant bulb vs 58 micomol/m^2/s for AgroBrite 6400K @ 12", with LiCor LI-190). With the non-uniform sensitivity curve of Seneye's PAR meter, it might be tricky to compare the PAR of bulbs with different spectra.

I'm not sure how Seneye is measuring so-called PUR, and I'm guessing that they get an approximate spectrum, and calculating the proportion of red and blue regions. PUR isn't something used frequently in science, but it is a crude way to get some ideas about yield photon flux (YPF). In plants, we used McCree curve to convert PPF (or PPFD) to YPF (weighted by the efficiency of photosynthesis for each wave length). But with corals, it is a bit more difficult (since the symbiotic dinoflegella is inside of the non-transluscent coral tissues). If you use the action spectra of extracted zooxanthellae, you can digitized the SPD of bulbs, and calculate something similar to YPF, which would be less crude. But it has been shown that something like YPF doesn't completely capture the actual growth (partly due to the fact that McCree curve is measured under monochromatic light, as Dana mentioned in one of his articles).

 

[Bradley Keck]

I'm loving this! You all are bringing me back to my college days when I was a Chem major at Purdue! Of course, I switched majors to Physical therapy and graduated from IU So, I will leave the debating up to you guys. I am excited to see what you find out Mr. Riddle! I use a T5/LED combo. I run what I would consider be a less popular combo of one ATI aquablue special, 2 actinic, and one B+ with my Kessils. So far, I have been happy with the pigmentation that develops along newly formed exoskeleton and the preservation of the color from the corals I have bought. I have attributed this to running more actinic than most would through the T5's. (I am basing this on what I read on here when the topic of T5 combos comes up) Thank You for all your work!

 

[Ferrell]

Following along. Very interesting conversation although I will admit I get brain spasm from time to time

 

[terri_ann]

Hey dear, Merry Christmas!

You are still unpacking?!! All those years create accumulation[emoji6] lol Just giving you some grief [emoji8]

We truly appreciate all the information and help you give. Your generosity is unsurpassed dear! Thank you!!

Wishing you a Happy New Year for all things wonderful![emoji8][emoji8]

 

[arafas]

Hello Dana, have you heard about these ?

link : https://eyehortilux.com/grow-lights/powerveg-family/powerveg-fsuv/

 

[arafas]

Absence of proof is not proof of absence.

Sorry to quote this message, but what do you think about the t5 bulbs one message before? specifically the UV side.

 

[Dana Riddle]

Sorry to quote this message, but what do you think about the t5 bulbs one message before? specifically the UV side.

So sorry, I missed your message from the 2nd somehow. Plants can use UV-A for photosynthesis. With zooxanthellae, they can produce pigments (mycosporine-like amino acids or MAAs) that absorb UV below about 340nm (from memory, I'd have to look at my notes) so the spectrum of this lamp should be, for the most part, beneficial. I'll see if I can get a lamp. The nearest retailer is 50 miles from me, and I'm really backed up on work right now so it won't happen quickly. What I can do fairly quickly is use a black light and look at rates of photosynthesis using a PAM fluorometer.

 

[arafas]

So sorry, I missed your message from the 2nd somehow. Plants can use UV-A for photosynthesis. With zooxanthellae, they can produce pigments (mycosporine-like amino acids or MAAs) that absorb UV below about 340nm (from memory, I'd have to look at my notes) so the spectrum of this lamp should be, for the most part, beneficial. I'll see if I can get a lamp. The nearest retailer is 50 miles from me, and I'm really backed up on work right now so it won't happen quickly. What I can do fairly quickly is use a black light and look at rates of photosynthesis using a PAM fluorometer.

Not a problem at all you dont have to apologize, we are all busy. Also i cant seem to find the spectrum of a blacklight online. Do you or anybody here have a picture of the spectrum in hand or what peaks of wavelength it hits??

THanks

 

[Dana Riddle]

Not a problem at all you dont have to apologize, we are all busy. Also i cant seem to find the spectrum of a blacklight online. Do you or anybody here have a picture of the spectrum in hand or what peaks of wavelength it hits??

THanks

I'll get a black light spectral measurement tomorrow, but will say it's pretty much a bell curve peaking at the mercury line spike of 365nm.

 

[arafas]

I'll get a black light spectral measurement tomorrow, but will say it's pretty much a bell curve peaking at the mercury line spike of 365nm.

Thanks that would be awesome. Also you think the t5 bulb I posted earlier will harm anything since it's in the UVB range. I know that water filters most of the UV. So would this be beneficial or will make coral brown and harms the fish? Thanks.

 

[arafas]

Hey Dana, look what I found. I don't know how beneficial these would be. Maybe something you would like to test in the future

 

[Dana Riddle]

Thanks that would be awesome. Also you think the t5 bulb I posted earlier will harm anything since it's in the UVB range. I know that water filters most of the UV. So would this be beneficial or will make coral brown and harms the fish? Thanks.

Sorry. I got busy and forgot. Old age I guess. I'd be a little hesitant to use the Pure UV lamp. Fishes' eyes can be damaged by too much UV, but a diet rich in vegetable matter (containing mycosporine-like amino acids) could protect them. Also a diet of copepods that feed on algae should work too. The University of Hawaii published a book on UV in marine environments back in the 90's and I was fortunate enough to get a copy.

 

[Dana Riddle]

Hey Dana, look what I found. I don't know how beneficial these would be. Maybe something you would like to test in the future

I'll go totheir website and see if they have any UV warnings posted. A couple of those spectra look kinda scary.

 

[arafas]

Hello Dana, have you heard about these ?

link : https://eyehortilux.com/grow-lights/powerveg-family/powerveg-fsuv/

What is name of that book if you don't mind sharing. Thanks

 

[arafas]

I purchased one of these bulbs and i am trying it instead of ATI coral plus. Fingers crossed I dont create havoc. What should i watch for, what kind of changes. So far everything is doing good no issues.

 

[Dana Riddle]

Took me a while to get into he lab and warm up the spectrometer. Here's a comparison of a black light (from ReefBrite) and a UV/violet strip light from Orphek. The black light peaks at 367nm and the Orphek at 400nm. Ignore the amplitudes, the intent was to examine spectra, not intensity.

 

[arafas]

Hello Dana, have you heard about these ?

link : https://eyehortilux.com/grow-lights/powerveg-family/powerveg-fsuv/

Took me a while to get into he lab and warm up the spectrometer. Here's a comparison of a black light (from ReefBrite) and a UV/violet strip light from Orphek. The black light peaks at 367nm and the Orphek at 400nm. Ignore the amplitudes, the intent was to examine spectra, not intensity.

WOW. Thanks for this graph. So which one of these is more beneficial for corals and colors. Assuming that orphek will give you more POP?