Brown marks on leef :-(

I agree with GMSlave , it's both pH and nutrient burn due to the high level of Rhizotonic which is too strong as well as raises the pH very much, so it goes in the soil and causes fluctuations. At this stage , you're better off making a spray with the rhiz 1-2ml/L spray twice to six times a day, this brings the auxin (growth hormone) direct to the plant. reduce feeding as much as possible and make sure you have plenty of run off if you're not in soil. Hope this helps ! 🚀