Download free app to measure the light and was curious what it should read for seedlings. I checked mine and it read about 550lux with lights 30” from seedlings.
It probably means 5500 lux and that would be ok for seedlings. Its about 80ppfd . Take your lux value and divide by 68 to get an estimated ppfd value
Here are the lux ranges to shoot for during each stage. I could never find a free Lux Meter App that would read over 20k or 30k. I bought a Dr. Meter Light Meter per Tbone's suggestion and I am glad that I did. Its a lot better being able to hit the exact #'s rather than guessing or lowering your lights until your plants tell you to stop....lol. Hubbabubbasmelloscope Quantum Board Grow