Nutrient Burn?

100% potassium deficiency..........the dark leaf edges are the sign.........nothing to do with calcium or magnesium......and not "nutrient burn" either. Plant looks very hungry..........needs nitrogen, potassium and phosphorous. Start gently........half strength once or twice, then go to full strength. I would suggest feeding no more often than once a week though. I also hope you are growing at 18/6 and not abusing your plants at 24/0...........but without a diary........

looks more like a calcium or magnesium issue than straight nutrient burn. Autos can be a bit sensitive, so don’t overcorrect just keep your feed light and balanced. If the spots stop spreading, you’re good. Flush only if you see crispy tips or clawing

What are you feeding them? They look more lemon lime then the typical healthy grass green I am used to seeing. I have a feeling the feed used is to low or inadequate. Best to start a diary lots of other questions as well. would be curious what your lighting schedule is as well. You can not reply to your own questions anymore as GD "growdiaries" removed that option because of dumb people that made a fuss about it.

hey 👋 It looks more like a nitrogen and potassium deficiency If you’ve only just started fertilizing, keep going with the proper doses without trying to correct it by adding more fertilizer : you might end up burning your plants You should soon see the new leaves growing healthy.