I have a couple young clones exhibiting the same symptoms. The leafs are curling down and have a leather appearance. It also seems the leaf tips are dried out and or burnt. Anyone have a clue what's going on here? pH: 5.8-6.3 It takes 2-3 days to drift from 5.8 to 6.3. pH is stable. ppm: 800 floranova nutes lighting: 1000 watt HPS ~30 inches from clones.
Yeah looks like over fert. If it trickles uip to 6.3 then start the ph at 5.2 or so then if it moves up it stays under 5.9 which is about the highest you want it to go.