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40k lux. Should I get closer ?

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Hello guys. So today I bought lux meter. My plants are in 3 rd week flower. One side plant is tall but I put it on the side and top canopy is 10 inch away from 530W led light. And gets 40k lux. All middle is 20 inch away and gets 40k aswell. Should I get light closer so most of the parts would get like 50k ?
 

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Hello guys. So today I bought lux meter. My plants are in 3 rd week flower. One side plant is tall but I put it on the side and top canopy is 10 inch away from 530W led light. And gets 40k lux. All middle is 20 inch away and gets 40k aswell. Should I get light closer so most of the parts would get like 50k ?
Which light do you have? Might be able to find a conversion for it that is exact. Otherwise your numbers will be off without the proper SPD or rent a PAR meter.

Rent a meter and you can do your own mappings with precision or even map out different dimmer settings.
 

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Which light do you have? Might be able to find a conversion for it that is exact. Otherwise your numbers will be off without the proper SPD or rent a PAR meter.

Rent a meter and you can do your own mappings with precision or even map out different dimmer settings.
Lux meter is not good enough? This is the light
 

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Lux meter is not good enough? This is the light
No, lumens are for humans. Photons are for plants and PPFD measures the amount of light hitting a certain point.


Their ppfd chart shows 21" from the canopy will get you 500ppfd minimum on the edges and over 1000 directly in the middle. I'd work with their recommended height unless you get a PAR meter or you contact them and ask for a SPD conversion factor so you may measure with your LUX meter.
 

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No, lumens are for humans. Photons are for plants and PPFD measures the amount of light hitting a certain point.


Their ppfd chart shows 21" from the canopy will get you 500ppfd minimum on the edges and over 1000 directly in the middle. I'd work with their recommended height unless you get a PAR meter or you contact them and ask for a SPD conversion factor so you may measure with your LUX meter.
Mmmmmm... what ?
 

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Mmmmmm... what ?
They are wrong.


Lumens are for Humans
Now that we understand a little about the types of light, we can talk about how to measure it. For human applications, like lighting homes or workplaces, the intensity of visible light can be gauged by measuring radiant flux (or power), which is calculated as the sum of visible light (in Watts, or J/s). This metric, however, can be misleading because systems that fail to produce the full range of visible wavelengths can still produce high radiant flux values. For example, a lighting system that produces high levels of violet and red light might have a high overall radiant flux output, but since the human eye is more sensitive to yellow and green light, the light wouldn’t seem as bright as the radiant flux measurement suggested.

Instead, measurements of luminous flux are much more meaningful. This metric, which is expressed in lumens (lm), is similar to radiant flux but is weighted according to the sensitivity of the human eye to different wavelengths of light. Accordingly, light sources with higher lumen ratings are perceived as brighter. However, because the human eye is most sensitive to green/yellow light (550 nm), the metric is heavily biased toward these wavelengths. This means that measures of luminous flux underrepresent red and blue wavelengths and, consequently, that luminous flux is a poor indicator of the usefulness of light sources to plants, which mainly rely on red light for photosynthesis. For this reason, measures of luminous flux and lumen ratings are inadequate for assessing and comparing grow lights. Beware that lux, foot candles, and candelas are all additional measures of luminous flux. These units of measurement are based off the lumen (lm) and are equally inadequate.
 

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They are wrong.

So let me get this straight. Queen seeds and the rest of the internet is wrong , and you my man are right ? I’m not arguing, have your moment of fame :DD
By the wayS this guy has 200k subs, but what ever, he’s wrong to :D
 

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So let me get this straight. Queen seeds and the rest of the internet is wrong , and you my man are right ? I’m not arguing, have your moment of fame :DD
By the wayS this guy has 200k subs, but what ever, he’s wrong to :D



Lights have spectral distribution and based on that SPD one can accurately determine PPFD with a Lux meter. Many are unique and not shared so usually a Lux meter reading will be 20%+ off in it's reading. Lux meters aren't designed for horticultural applications so they aren't accurate without am SPD conversion factor.


Good luck with your lighting situation, hope I was helpful. Divine blessings from the Canna gods :bong: :d5::dancer:
 
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