Apologies for the blurple lights but this problem seems to be getting worse. Soil is a mix of black gold and fox farms ocean forest. Under 300w total of led, 2 blurples and a spider farm. I'm feeding fox farm trio, very very low doses however. The auto with the burns is barneys farm gelato glue, the other one which is doing great, is a freebie feminized. The water is ph'd at a 7, which I've been attempting to drop slightly in case that is part of the issue. Doesnt seem to help. I ordered calmag to see if that helps as well. I should note she is still growing extremely well. But the burn is spreading and I can't figure out what is causing it except maybe aeration issues since I didn't cut the soils with any perlite or vermiculite. And very little nutes however my guess is she could need a firm flush maybe she is building up salts? I will cal mag this weekend when it arrives. Help if any is greatly appreciated.
Those are very atypical marks. This might be leaf septoria. Did you spray something on them? Even water can magnify the light and cause burns. Could also be pH related.
I neemed only the soil previously. And the tap here is slightly base, probably a 7.5. I'm thinking it needs flushed I'm worried a salt buildup has occurred but honestly I'm lost at this point. She is still growing a lot day to day. No water should have got on those leaves I can tell they are burning because the dark spots got worse. And they are yellowing. Previously they were just dark brown. Now they almost look like burn holes.
Oh also. I have another plant next to her and she is on the exact same schedule and everything. She is a freebie seed and still doing great albeit a bit slower growth.