Isn't it possible to measure the PAR output for another light source at a distance from the source with a known Foot candle intensity and compare to the LEDs etc. I was thinking about doing that in my current setup. Any objections to this idea?
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I am just a layman in terms of lighting, but it seems to me if you are measuring the milimoles of photosynthetically active light that if you measure this value for say a metal halide at 3,500 fc then you can then search for the proper distance from the leds using that value of PAR as a guideline.
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All you would need is a FC meter, a PAR meter and a reference light.