Why do people run 6500K bulbs?

Discussion in 'Aquarium Lighting By Dana Riddle' started by Velcro, Dec 4, 2017.

  1. Dana Riddle

    Dana Riddle Well-Known Member Staff Member R2R Supporter Build Thread Contributor Expert Contributor Article Contributor

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    Be careful with graphs like this. Looking at this graph leads one to believe spectrum based on these curves shown is somehow best. I'm not saying success can't be achieved making decisions on this info, but there's a lot more to the story. Look at the line showing absorption for carotenes - this includes beta-carotene that can actually act as a photo-protectant (beta-carotene is found in carrots (! -carrot-tene) and makes them appear orange because they absorb violet/blue light.) Hence, they compete with chlorophylls for blue light. The same can be said for xanthophylls - oxygenated carotenes - they absorb blue light as well. In short, merely looking at the graph leads one to think blue light is most strongly used in photosynthesis. Based on PAM fluorometry experiments' results, red light is most efficient while graphs like this suggest otherwise.
    It is no accident that fluorescent pigments that absorb UV-A, blue and violet light and hence subtract from light available to photosynthesis if blue light is of high intensity (relative to what is seen in nature.) Coral fluorescence is another tool in the arsenal of zooxanthellae photoprotection.
     

  2. Big E

    Big E Well-Known Member

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    Sorry, I was trying to explain how it all ties together that the spectral plot of whatever light source you choose is going to determine best growth and color. I don't have experience with that particular T5 bulb and that's why I mentioned the 6500k Iwasaki as a comparison. The peaks in the Blue+ & Coral+ help us see the colors better and also help with reflection, so the results would probably overall be more pleasing to the eyes, but as far as better growth it would go to the 65k bulb if it mimics the sun at shallow depths. MH, T5, LED isn't important as much as what they are each capable of producing for what the corals need, or what spectrum you are trying to achieve.

    All that information is out there...... Dana's articles on pigments and many other sources can help quit a bit.
     
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  3. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter R2R Excellence Award Reef Squad Photo of the Month Award

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    Oh, I absolutely am Dana , that was the fast find as a rough example.

    I actually had it on my phone to explain to a member how to look a spectrum when selecting a light. The SB is heavy in the royal blue visually etc...
     
  4. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter R2R Excellence Award Reef Squad Photo of the Month Award

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    Did corals change ?

    Lol.
     
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  5. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter R2R Excellence Award Reef Squad Photo of the Month Award

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    Ati.

    IMG_0726.JPG IMG_0727.JPG
     
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  6. BigJohnny

    BigJohnny Well-Known Member

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    I was just playing with you Dana on the old vs new thing. So which lamps contain mercury, I have no idea? My understanding is that halides produce significantly more uv-a then any t5 bulbs. Also, not many true uv-a leds in fixtures, although reef Brite makes a uv-a bar now.
     
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  7. BigJohnny

    BigJohnny Well-Known Member

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    Yea, although the reason I was saying metal halide vs t5 does matter is that usually a 6500k metal halide produces more uv then a 6500k t5 as far as I understand. They can also be very different overall. I was also just trying to eliminate variables. So why don't you run any 6500k t5s on your tank, just don't like the look?
     
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  8. jda

    jda Well-Known Member

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    HID like HPS, MH and all Fluorescent bulbs have mercury and make UV at different levels. Depending on the tube, a T5 could put out just as much UV and IR as a MH bulb.

    UVL Super Actinic was once (and still is) an amazing VHO and T5 bulb for color and pop that has a significant amount of the output below 400nm. Their Actinic White is a 50/50 bulb that still has a bunch of output below 400, but also is a bit pink. Most of the true actinic bulbs are full of spectrum down to 350 - Giesemann has a lot of low output.

    I have not seen very many true UV diodes in LEDs. Even the few that I have seen are like 380nm. Most manfs fib/lie and call their 410 and 420 UV, but they are not, of course.
     
  9. jda

    jda Well-Known Member

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    The UVL T5s are also good candidates to be overdriven to VHO T5 specs.. about 88 watts a bulb IIRC. Ed would know more about this than I do.
     
  10. Dana Riddle

    Dana Riddle Well-Known Member Staff Member R2R Supporter Build Thread Contributor Expert Contributor Article Contributor

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    Metal halides and all type fluorescent lamps contain mercury. The spikes in the spectrum of fluorescent lamps shown earlier are due to mercury (365, 405, ~430, 545, 575 nm (I'm doing these from memory) - fluorescent lamps are in fact low pressure mercury lamps. The type of glass used makes the largest difference in UV actually making it out of the lamp. The UV-B lamps marketed for use in reptile husbandry use a glass that transmit the UV instead of absorbing it as most fluorescent lamps do. Same with UV lamps used in sterilizers - their glass transmits UV-C. Yes, you are correct, MH lamps usually make more UV due to their wattage (even seen a 400 watt fluorescent lamp ;).) UV LEDs are expensive and aren't often seen. The LEDs I've tested have a peak emission around 390nm (again from memory.)
     
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  11. mcarroll

    mcarroll Well-Known Member R2R Supporter R2R Excellence Award

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    Added the GE 6500K spectrum that someone mentioned to post #56 for comparison.
     
  12. Dana Riddle

    Dana Riddle Well-Known Member Staff Member R2R Supporter Build Thread Contributor Expert Contributor Article Contributor

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    That's a pretty good chart you posted. It's unusual to see this many photopigments absorption spectra graphed together. I saw it as an opportunity to discuss what the carotenoids actually do. Beta-carotene does transmit some absorbed energy to photosynthesis but it is with very low efficiency, and, in corals' zooxanthellate at least, it is generally regarded as a photo-protectant and anti-oxidant. Even when armed with this knowledge, it is difficult to distinguish exactly how these photo-pigments influence photosynthesis. PAM fluorometry can examine rates of photosynthesis, and absorbance of light must be measured in order to accurately report this Electron Transport Rate, or ETR (which is why I generally report Relative ETR instead of absolute ETR.) However, the PAM fluorometer can easily distinguish how light is utilized - photochemistry, chlorophyll fluorescence, and so on.
    One of these days, when all the ballasts I shipped are unpacked, I'll run a comparison between ETRs when using a Iwasaki DL lamp and another lamp(s.) This project has been on the backburner for a LONG time.
     
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  13. mcarroll

    mcarroll Well-Known Member R2R Supporter R2R Excellence Award

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    It's notable from all those 6500K graphs I posted that there are large swaths of "missing spectrum" from all "reef" 6500K bulbs by way of comparison with the Iwasaki or Radium counterparts – which really are remarkably similar to sunlight, all things considered.
     
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  14. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter R2R Excellence Award Reef Squad Photo of the Month Award

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    The owner is pretty on top of it. He's been around a long time.
    Before I bought them I vetted him pretty hard. He's in with a lot of the older diy guys. Jedimasterben is the author of that post I linked.
    Pretty knowledgeable crowd.

    And yea , I've booked marked that post lol. Along with a bout a dozen others like that. Those are the mechanisms I'm studying now. I am still kind of a newb after all.

    Or does still facinate that even a proven spectrum and method will still be ignored by so many in favor of looks. That's with led , the sb (too pink) , the 6.5 MH , that geismann etc , even when the question is looking for the "best".
    Fortunatey my other passion is in Social anthropology and behavioral study. ;Cyclops
     
  15. jda

    jda Well-Known Member

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    This got me wondering about how the 6.5K Iwasaki looked against the Radium for pure output, so I ran the graph below on the same chart. If most would agree that coral are better colored and faster growers under the Iwasaki and just rendeerd poorly, then perhaps the coral are just "surviving" under the lower total output of the Radium, which is less than half. Somebody needs to make a bulb with the same output as the Iwasaki with the blue spike of the Radium.

    [​IMG]
     
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  16. Dana Riddle

    Dana Riddle Well-Known Member Staff Member R2R Supporter Build Thread Contributor Expert Contributor Article Contributor

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    Perhaps you can explain to me my behavior. LOL. As for the lighting part of it, I'm a pilgrim myself. There are processes in photosynthesis that are not understood by science and this is after years of studies of terrestrial plants. Coral biologists/phycologists didn't even get around to reporting PAM fluorometers' results until the late 1997 or 1998. I bit the bullet and bought a fluorometer in or about 2001 for about $4,000 and upgraded to a newer model a few years later. It was remarkable to see the advances made in understanding how energy is used in photosynthesis as described in the maker's user manuals, and with the advent of PAM fluorometers using different colored LEDs as an excitation source, I'm sure the advances made in the next few years will be equally remarkable. See here:
    http://walz.com/products/chl_p700/multi-color-pam/introduction.html
     
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  17. Dana Riddle

    Dana Riddle Well-Known Member Staff Member R2R Supporter Build Thread Contributor Expert Contributor Article Contributor

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    Good comparison! Note in particular the wavelengths up to about 550nm for peridinin and far-red for PS I stimulation.
     
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  18. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter R2R Excellence Award Reef Squad Photo of the Month Award

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    Folks seem to not like the answer "science doesn't yet fully understand " Esp if it's not from a scientist.
    Like the greening in some corals , the undiscovered clades etc. and the effect of different spectrum intensitys on colors.
    personally, I like being able to watch it all happen and evolve.
     
  19. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter R2R Excellence Award Reef Squad Photo of the Month Award

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  20. Dana Riddle

    Dana Riddle Well-Known Member Staff Member R2R Supporter Build Thread Contributor Expert Contributor Article Contributor

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    The hobby, through anecdotal evidence, will continue to direct coral scientists to unexplored arenas. It was a hobbyist in Moscow, Russia who showed his coral reef aquarium to a scientist, and this experience eventually led to a revolution in the biomedical field. Hobbyists correctly reported that blue light was responsible for inducing fluorescent pigments, and, again, this led to cloning of fluorescent proteins, splicing them into human tissues - this helped science visualize how cells reproduce, untangled here-to-fore masses of nerve tissues, and so on. There is a particular interest in orange-red to red fluorescent pigments as these produce light that is most efficiently transmitted through human tissues (hold a flashlight to the palm of your hand and observe the red light shining through on the other side.) As for the hobby side of things, I published the first article exploring the use of LEDs in a coral tank back in 2001 (or was it 2002?) In this article, I reported that red light induced bleaching in zoox within a Pocillopora meandrina. Man, did I take a lot of heat for that article
    No reason you can't be a part of it. Our understanding of fluorescent coral colors began with a scientist seeing a reef aquarium in Moscow, Russia. This scientist eventually cloned the pigment by splicing DNA into E. coli bacteria. Mass production led to a revolution in biotechnology, by inserting different colored fluorescent proteins into nerves scientists could untangle the masses and gain better understanding, cell division become better understood. Orange-red and red fluorescent proteins gained the most attention since the human body transmits these colors best (hold a flashlight to the palm of your hand and see the red light shining through.) Another important contribution was the anecdotal observation that blue light induces the production of many of the fluorescent proteins. This too played a starting role in the biotechnology revolution. On the hobby side of things, a fellow I know pretty well played around with blue and red LEDs in 2001 and reported their effects (coloration and bleaching, respectively.) That red light might induce bleaching or regulation of zoox populations was not new, but the effects of narrow band red light had never been reported, and caused a minor stir within the pond of reef keeping. Peer-reviewed literature would later confirm the detrimental effects of intense red light. Of course, there are hundreds more stories. To make a longer story short, it is difficult to over-estimate the observations made by aquarists.
     
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