Hi there Gelatoman, i have to disagree with my colleagues here : it's absolutely not temperature or light stress. This is a pH and root zone problem ! you can see this because of the discoloration "splotches" and the wrinkled leafs as well as the tips and curling serrated edges of the leafs. In hydro you need NPK + micro + additives. Now you have NPK+ micro. so you need additives to fix the root zone and help with breaking down the nutrients. TRy to use something like humic or fluvic acid or something biological like "great white" for hydro. What's happening is that there are bad microbes and mold affecting the root zone. After you fix this with additives you should also consider "root pruning" technique, that when you lift the plant outside the pot and actually cut the problem roots (never more than 15% of the total root mass!) with a scissor ... this sounds crazy, but this is the "right way" for hydro. I hope this helps ! π