I moved the fixture up to 30 inches at 75% for nowIf you have a 480W LED, it might still be too bright. I think you have it at 75% and 24 inches? If so, that seems like a lot to me considering the stage of your plant.
My thinking is that if I'm wrong, somebody's going to correct me here. Either way, you get a bump so we'll see.
Ah, okay. Maybe it's something else. It seems like I have read conflicting information about light burn. Some writings suggested a grower would be in the clear with nice-looking new leaves. But, I also remember reading elsewhere that it shows on older leaves first because the damage takes a while to accumulate.spots are on the oldest leaves only, it seems. new growth looks free of spots. spots are on 2 of 3 plants on same older growth.
im thinking so as well..... changed my lighting distance and hasnt become worse... yet.Happens to me in FFOF sometimes, I thinks it's either light stress or the soil being too hot, ussually doesn't stick around for long.