top leaves curling dieing

Have been away for a week they all looked fine last sunday but know?
10 weeks old El Nino under T5 lights 18hr day 22 58 RH night 15 45 RH Bio-grow 1mm per lt watered ever 4/5days 24hr extraction & movement fan

looks like nute burn or ph imbalance causing nute lockout. flush it and measure ph of ur soil bring it closer to 6.5 if its off.