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Thread: Led, par and tent size

  1. #1

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    Default Led, par and tent size

    Evening all,

    With led the important thing appears to be par. So for example I've read that anything over 700 umols is what's needed for flowering. But could you have too much par in a smaller space such as 60x60? Or am I confused and talking out my arse?

    That prakasa ironman is running just now only knocks out 420 umols from what I read meanwhile a meizhi 450 (real usage about 200w) is giving out about 700 umols. Obviously one uses about twice as much power so kinda makes sense it would have more par.

    So really my question is if you're gonna spunk a 100 quid on a led would you go for the higher par value (within a 60x60 tent)

    Does that make sense??
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  3. #2

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    Do you mean total light or light density?

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  5. #3

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    Quote Originally Posted by gardro View Post
    Do you mean total light or light density?
    Mate I don't really know anymore, I suppose I mean density and maybe even intensity for that size of space

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  7. #4

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    We need to be quite careful with units when it comes to light - PAR is a part of the electromagnetic spectrum, the range of light wavelengths which can be used by a plant for photosynthesis. A micromole isn't a unit of brightness, it's a static unit of output - so, you can have μmol/s to quantify the PAR light emitted over time, or you can have μmol/J which quantifies the efficiency of the light.

    The numbers you mention look like they'll be μmol/m^2/s, which is a measure of brightness in a sense - it's how much light passes over a given area in a given time if that makes sense. Probably the biggest variable to be careful of if using that measure to judge a light is what height the measurements are taken at, since obviously the brightness will be higher closer to the light. The other big variable is the spread, which will obviously be worse closer to the light. Most decent lights will give you a diagram of the spread that will show you values over an area rather than just directly underneath.

    You can certainly have too much output for a given space and height, but there will hopefully be someone a bit more knowledgeable than me who can weigh in on that properly.

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    The migro emits 239umol per second (ppf). I doubt mehzi have even measured theirs

    The migro is perfect for 60x60, bearing in mind the reflective tent will further increase the par density ( density = intensity as youve mentioned )

    I can get 1500ppfd from a 18w led. Its not very useful though.

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  11. #6

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    Quote Originally Posted by gardro View Post
    The migro emits 239umol per second (ppf). I doubt mehzi have even measured theirs

    The migro is perfect for 60x60, bearing in mind the reflective tent will further increase the par density ( density = intensity as youve mentioned )

    I can get 1500ppfd from a 18w led. Its not very useful though.
    Thanks I think I'm getting there, just using those figures as examples from what I've read. I've seen some pretty kick ass results from thsee cheaper led panels. It's confusing stuff

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  13. #7

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    I got lost at ''Evening all.'' O.o

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  15. #8

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    For 60x60cm tent. Mars pro II 80 can offer you enough PAR value.

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