Have you thought about maybe bringing up that lights off temp, so that the day/night diff is less than 10*?Lights
On
82f 50%
Off
68f 45%
Co2 850
EC 1.7 5x daily
PH 5.8 thru 6.2
Leaf temps in 80's. Varies with the kra kra canopy. Lol
The 'spike' at lights off is probably more than the 14* diff you've said above, no? Maybe you're saying 68* is the absolute minimum/the low 'spike' (valley)?