nowstopwhining
Too many brownies
do you not see the totally fried and curled new growth along with the curling leaves????yeah I agree what is wrong with it?
Honestly though they may not be overnuted it could also be salt or ph issues.
too high or low of a ph will cause a nute lockout that looks similiar to burn i believe and so does salt buildup.
I dont think its salt buildup though because youve been changing the res, not too sure though never grown hydro.
Could be ph
whats your grow room temps, and the temp at the canopy of the plants?