that is interesting, I was skeptical when you said a phone app was measuring PPFD but after a quick google search i see phones have a built in light sensor to adjust the screen brightness according to ambient light? The more you know. My phone is getting on the older side and I don't think it even has that function but I am curious now. If you have found a way to make it accurate and save money on an expensive par meter than kudos to you

Newbelinginaz said:

So I started using the android app "PPFD Meter" and calibrated my phone to my lights specifications. The phone was 55% off, so with calibration and some education on DLI I am in the Dank Zone finally after sacrificing many seed as a new grower.

So do yourself a favor and "Calibrate, Calibrate dance to the music"

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Absolutely it depends on the phone make and model, screen protectors etc. Always best to find someone with a meter and calibrate it. Local grow stores can prob help ppl out.