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Tried asking this on other forums but no replies so hopefully you can help me. (Again)

Is there a link between LED lights with higher lumens and higher PAR or could a light with 800 lmn still have a high par value. I was looking at a 50w floodlight with 5000lmn and a colour temp of 6500k but I have no idea what the par value is.
Trying to get more light into my tank and might just look at 2 nicrew skyLed plus lights where the par value is known..
 

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The answer is sort of. Lumens is how bright something looks to the human eye. Par is the spectrum that plants use. The two overlap but are not the same. In practice however brighter lumens typically will mean more par/ppfd. To get a rough idea as to how much par is being put out, use a lux meter or the lux meter app on a smartphone take the lux and divide by 80. This will give you a rough idea as to par/ppfd at the given distance.
 

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The answer is sort of. Lumens is how bright something looks to the human eye. Par is the spectrum that plants use. The two overlap but are not the same. In practice however brighter lumens typically will mean more par/ppfd. To get a rough idea as to how much par is being put out, use a lux meter or the lux meter app on a smartphone take the lux and divide by 80. This will give you a rough idea as to par/ppfd at the given distance.
OR use this with a few canned conversion factors .. O/P would use low CRI 6500k led

100Lux = 1.34 PPFD
74.6 soo or 80... ;)

Trickier to convert lumens to lux then lux to PAR

And you still have the issue of lux being center weighted around green
Measuring 100 Lux under pure blue light is 11.56 PAR
Divide by 8.56
For fun...

Seems to be a decimal discrepancy there.. so not for fun..
Hmmm NOTED in comments..
CORRECTION: The conversion factor is off by 1 decimal point e.g. please use 0.025 instead of 0.25. ALSO the 881E model range is 0 to 300,000 lux. Sorry for the confusion. Shane
 
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