Bruce Banner Auto

Hey mate, Yeah bluelab is arguably the best ph pen on the market. Water cant be contaminated as its RO. Your feed is at a good ppm. That only leaves a possible issue with the coco. How much water have you flushed with? You should flush with 3x the pot volume (e.g 10L pot needs 30L of water) If you have flushed that way I'd be changing the coco.

Hi there, Even though you can't overwater in Coco, plants at this age in big pots can be drown easily after watering if you are giving water with alot of run off.But don't worry they should be bounced back.My advice is to give just enough water untill they are fully matured or completely enter into vegetative stage.At your plant age, 100~300ml per day would be enough for now.Happy growing... ✌️

Looks like it was a ph substrate issue. Old leaves won't repair themselves. New growth looks ok. If your run off ph is in check and your giving proper nutrition your problem might be solved. Just plant is stunned likely. They can surprise us though and take off.