nutrient film technique

The flower is looking even better this week as you'd expect :-) She levelled out at 34" i dont think shell get any taller. Got a bit of leaf curl on the tips but i am pushing it with the food level. I'm flashing 1.3 ec and ph is around 5.8. Could be a the heat from the light? The tangilope on the same tray looks like it can cope with this strenght feed. Have a nice thick white root matt although slightly stained because Part A feed of canna is red. Added PK13-14 This week as it 5th week of flowering plus I've put a fish tank heater in to keep water around 18-20C as water temp is bitterly cold