Sickness or too many nutrients?

too much nutrients,piling up in the soil as plant can't drink all it is starting to drop soil ph which makes it even harder for plant to absorbe. do a proper flush with pure water with at least 3x of pot size.do not adjust ph of the water.

You have a Calcium/Magnesium deficiency, the yellow/tan lines between the veins is Magnesium, the spots leading to dead spots (necrosis) in the leaves is calcium. Cant see your grow for some reason so I always begin with PH before adding cal-mag. Kind of blind not sure why the grow isnt showing. Something is either locking them out or there is not enough uptake(PH).

@WeedManHD it could also be an iron deficiency the way the leaves are turning yellow like that Also the leaves look very swollen don't overwater when they look like that Good luck mate 👍

This looks like either led light burn or wind burn. If you have a fan blowing on that side of the plant then that is the issue. If you are using led, I would move it up away from the plant a little. Good luck!

In my opinion, it looks like you’re suffering from either calcium deficiency or calcium lockout. I’d feed the plant some calmag or epsom salt for definitely. And for lockout just flush with water for a week.

In my opinion, it looks like you're adding too much nutrient, they look they're turning a darker green and getting shinier with them clawing down. Try easing up a little bit.

I am quite sure your plants aren't burned. I think you may have calcium, maybe phosphorus deficiency. Overall your plants looks healthy, it is normal for lower leafs to start yellowing and then dying even if this is not what's happening to yours.. You should stop root nutes because you don't need them anymore, I use root stimulator just during the first and second week, try to push a bit with green sensation I think it could help, just pay attention. Good luck with your grow ciao ☀️