Light Distance - Question for all

Safest thing is to use a light meter. Cheapest way is to get the photone app. I tried both and surprisingly the photone app was very precise with my iphone and a damper (a piece of white paper taped around the top 😅). It was pretty much the same reading with either the app or the meter. Photone also has a light suggested chart on their website that not only saves energy, but it also prevents you from burning your plants. Overall, I take this all with a grain of salt, because if you pay attention to your plants, they will communicate with you. So, in conclusion, crank the light in flower, and watch the response. Adjust accordingly to your personal set up. Blessed growing!