# lumens in finnex lights



## AvalonExotics (Jan 30, 2015)

how many lumens are the fugeRay LED+ moonlight series? we just ordered 18", 24", 36", and 48"

thanks....i dont really understand all the PAR stuff although im not opposed to a lamens explanation


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## Dolfan (Apr 8, 2005)

Hoppy has a great article that explains PAR....

http://www.plantedtank.net/forums/showthread.php?t=184368

I'm not sure of exact numbers, the Planted + LED's are designed to put most tanks in the low to medium light range depending on how deep your tank is. I have a 36" on my 40 breeder and it is right in the middle of low to medium, as least it seems to me. Works great, you will be happy.


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## jeffkrol (Jun 5, 2013)

AvalonExotics said:


> how many lumens are the fugeRay LED+ moonlight series? we just ordered 18", 24", 36", and 48"
> 
> thanks....i dont really understand all the PAR stuff although im not opposed to a lamens explanation


Graph on the left is what is usually measured w/ a "lumen meter"...
Graph on the right is PAR BUT not what is measured:











Li-Cor quantum sensor (PAR) response:









for fun to muddy the waters even more..
Yield Photon Flux
Weighting factor for photosynthesis. The photon-weighted curve is for converting PPFD to YPF; the energy-weighted curve is for weighting PAR expressed in watts or joules.

PAR as described above does not distinguish between different wavelengths between 400 and 700 nm, and assumes that wavelengths outside this range have zero photosynthetic action. If the exact spectrum of the light is known, the photosynthetic photon flux density (PPFD) values in μmol/s can be modified by applying different weighting factor to different wavelengths. This results in a quantity called the yield photon flux (YPF).[1] The red curve in the graph shows that photons around 610 nm (orange-red) have the highest amount of photosynthesis per photon. However, because short-wavelengths photons carry more energy per photon, the maximum amount of photosynthesis per incident unit of energy is at a longer wavelength, around 650 nm (deep red).












> Typical PAR action spectrum, shown beside absorption spectra for chlorophyll-A, chlorophyll-B, and carotenoids


http://en.wikipedia.org/wiki/Photosynthetically_active_radiation
http://www.iquaticsonline.co.uk/blog/what-is-par


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