"LUX METER"

[Nartak]

I totally agree and that is the sole reason i have maintained a 16" distance minimum! I just witnessed hardcore nute burn on a couple leaves of 2 plants but they can suck on that one,once they realize its flower time they will drink up the shitload im giving them! 2.4 is my current limit!

 

[Nartak]

Oh it's on alright!!!

 

[Mykshank]

Does lux meter work for LED’s also?

 

[smoorman]

Not for blurple but it will for "bright white" quantum boards.
https://www.growweedeasy.com/lux-meter
A good read. There are others.