Par from T5 vs par from led

Discussion in 'Aquarium Lighting By Dana Riddle' started by Eric23, Feb 8, 2018.

  1. Eric23

    Eric23 Active Member

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    Can someone explain why par from a t5 vs par from an led is different ? More to the point why high par from a t5 is less likely to burn acro then high par from a an led fixture
     
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  2. Crabs Mcjones

    Crabs Mcjones Millepora Maniac Staff Member Team R2R R2R Supporter R2R Excellence Award Reef Tank 365 Article Contributor Build Thread Contributor Partner Member 2018

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    With T5's its evenly disbursed par, with leds, they use reflectors that focus the light down and can cause par hot spots.
    So here is an example of T5 par coverage from the Aquatic Life T5 fixture
    upload_2018-2-8_14-35-15.png
    And here is a graph for a Radion G4 Pro
    upload_2018-2-8_14-37-11.png
    As you can see, the leds have a pretty good hot spot right under the fixture whereas the T5's have an even blanket of par coverage. Also with LEDs there is alot more shimmer, which causes quick bursts of high par to corals, whereas T5's dont give off alot of shimmer so the corals get continuous par amounts with little fluctuation.
    I hope this helps with your question :)
     
  3. anthonys51

    anthonys51 Active Member

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    Hi Eric it’s all about even output. Led tend to be more like lasers and t5 especially ati with the reflectors tend to be more even spread Now lights like the radion have tired to counter this by making lenses that spread the light more evenly but still doesn’t compare to ati t5. Honestly how can one single bulb cover 36 inches as evenly as a 4-8 bulb that’s 36 inches long It’s why I prefer 3 radion xr15 to cover a 48 inch tank than 2 xr30
     
  4. XNavyDiver

    XNavyDiver Insightful answer loading... please wait. R2R Supporter R2R Excellence Award Build Thread Contributor

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    untitled.png
     
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  5. anthonys51

    anthonys51 Active Member

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    Also have to do with the ability to get a broader range of color out of a single bulb. Where led can only be one spectrum for each single led bulb. Technically isn’t where t5 is yet
     
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  6. Eric23

    Eric23 Active Member

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    Right I knew about the hot spots and the spread but I guess I didn't think about shimmer having an affect or singular beams of light from LEDs hitting the coral. I was under the assumption that regardless of how it was delivered to a specific spot that par was par... So if I single point in a tank was getting 400 par from a t5 it would be equal to a single point of 400 par from an led but it's not.
     
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  7. XNavyDiver

    XNavyDiver Insightful answer loading... please wait. R2R Supporter R2R Excellence Award Build Thread Contributor

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    The "point light source" effect is what motivated me into getting the diffusers for the radions. So far everything seems to love the t5's and the diffusers!
     
  8. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter Reef Squad Leader Photo of the Month Award R2R Excellence Award Build Thread Contributor

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    The par isn’t different , the quality (visual) and spread are different.

    Same as a t5 Vs metal halide.
     
  9. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter Reef Squad Leader Photo of the Month Award R2R Excellence Award Build Thread Contributor

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    It is basically yes.
    But it depends on the spectrum of the source.

    An led has the down fall of having knobs. So users can guess what’s best. A t5 has all the good stuff and we can’t mess with it.

    So you can get an led tonguve you 400 par buts a narrow spectrum. The t5 is premixed with a wider spectrum.
     
  10. chipmunkofdoom2

    chipmunkofdoom2 Always Making Something R2R Supporter Reef Squad R2R Excellence Award Article Contributor

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    +1. I think this also has to do with how bright LEDs appear to the human eye. Historically LEDs looked a lot dimmer than other light sources (T5s, MH), even at similar PAR levels. An LED fixture might have looked dim or not as powerful as the T5 or MH fixture it replaced, and as a result, the reefer may have cranked the LEDs up, inadvertently burning the corals with way too much light. PAR meters are relatively expensive, so relatively few reefers have them.

    Personally, I would pick up a cheap lux meter from Amazon or Ebay (with @saltyfilmfolks help I chose this one for just over $10). You can divide a lux reading by 40 for T5s (60 for LEDs) and get an approximation of how much PAR the light is generating. While this isn't the most accurate way to measure PAR, those conversion factors are relatively good, and it's much better than just throwing the lights on the tank and eyeballing it.
     
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  11. anthonys51

    anthonys51 Active Member

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    Also led suffer from more of the shadow effect than t5
     
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  12. Eric23

    Eric23 Active Member

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    From what I understand about T5 Spectrum not all of the spectrum is used by corals for growth. From what I understand about kessil LEDs is that regardless of how you set them blue or white the spectrum is tuned for Coral growth. If that's true then would hi par from a T5 be relatively equal to low par from the kessil being that the spectrum's are used more or less efficiently by the corals ? I guess a simpler way to ask would be is light from the kessil used more efficiently then light from a T5 because of the spectrum ? Or am I going way off ?
     
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  13. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter Reef Squad Leader Photo of the Month Award R2R Excellence Award Build Thread Contributor

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    If we hit only the nm corals use , the tank would look pink. (Red and blue )
    04C5091F-349D-4037-8EAE-C0F1894387B7.jpeg
    Not a promo , but look at where the cloryphyl and carotenoids are.

    The kessil logic thing is to make sure you can grow corals no matter where it’s set. It’s just more blue or less.

    I run my lights at a 1:1 white blue. Most of the useful stuff is in the blue end , yes, but I like that me red fish and red corals look red. You need red to reflect red so we can see red.

    Fortunately kessil doesn’t post any of thier spectrum or par or anything else , so we don’t know how much green ( middle green) they use. They need some as other wise it would be blue ish pink (they do use less red than some )

    Make sense?
     
  14. madweazl

    madweazl Valuable Member R2R Supporter Build Thread Contributor

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    T5s are created for very specific spectrums as well.
     
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  15. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter Reef Squad Leader Photo of the Month Award R2R Excellence Award Build Thread Contributor

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    Mine don’t actually. I have 3 B.B. in my 55 tank. It’s end to end Light. Like t5. In my 20x 18 I have a 16 x 8 box of light. So it’s a large source.
    I could have used a single a360 , but it’s a couple inches across. So yes. Shadows. Single source lighting. Film noir.
     
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  16. mcarroll

    mcarroll moved on R2R Supporter R2R Excellence Award

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    While any light source can cast a shadow, the "shadow effect" is not created by LEDs.

    The dreaded "shadow effect" is created when someone uses spotlights to light a tank where they meant to use strip lights.

    So some users might be suffering, but the LED's are not – they are just doing the job they were designed to do. ;)

    Shadows are perfectly natural in the wild BTW. You have to get VERY deep before they cease being a factor.

    The whole "shadow effect" concern seems unjustified to me considering the number of successful reefs that have grown up with AND without "shadowy lights".
     
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  17. anthonys51

    anthonys51 Active Member

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    The leds thst are long instead of the round set of lights might spread the light more even but you loss is kelvin spread The reason they cluster the lights on led like the radion and kessil are for an even spread of all the different kelvin’s of light the leds thst are long gain coverage but lose even coverage. If you look at world wide coral sps tank they had radion spread very close together and about 12 or more above the water versus the 9 inches the bar has
     
  18. anthonys51

    anthonys51 Active Member

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    I mean shadow like shadows in the water I mean let’s see if I can explain
    You take the radion g30. They cover 36x36.
    But if you place them 18 inches from the left side of your tank. If you happen to have a coral growing 12 inches from the end of the tank it will start to dye on the left side because it will get shadowed by the coral. T5 have the reflectors on top of the light and a longer light won’t have the sand effort. It’s why I spread even though you can spread your radion 24 inches apart it’s better to spread them 12 inches apart
     
  19. oreo5457

    oreo5457 Active Member

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    No...................not exactly..and certainly not in HIGH vs LOW..
    [​IMG]

    Random picked spectrum

    [​IMG]
     
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  20. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter Reef Squad Leader Photo of the Month Award R2R Excellence Award Build Thread Contributor

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    Kelvin spread ?

    Actually I belive they cluster the led ins kessil and Radion is becuse it’s cheap to make.
    Search back a few years and research something called the dream chip. Basically a kessil.

    But that has little to do with par and spectrum.

    Also folks forget , there’s a ton of metal halides that are just awful. Really expensive , terrible reflectors and made a huge hot spot. I actually have one in the basement. It’s horrble.
     
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