Hydro plant leaf curling issue

[Beowuuulf]

Hello,

please offer any advice or suggestions or diagnosis..

27 days since germination, the plants are curling like intense heat stress.

600 ppm of cal mag, grow, and micro nutrients
5.8 PH
65 f res temp
77 f tent temp @ 68% Rh all the time
Ppfd 250-300 umols maximum 400

initially I thought oxygen or calmag problem but new growth after res chiller added is still curling,

wtf is going on?

 

[Scolymia7]

if you have timer on exhaust possibly double check it. I bumped mine one time and it was off for couple hours while lights were on causing my room to hit temps in upper 90s for 2 weeks.

 

[pdasterly]

heat