leaves curling up why ?

Hi my seedling is jusy over 3 weeks old . 150w cfl on 18-6 temps around 75-80 n humid 45
Night 70-75 humid 35
Nft hydro
Feed water phd 5.8 n formulex 4 times a day starting couple days ago . Light around 3inch away . Since last 2 days the leaf tips are curling upm can someone help

Could be a bit warm. But it's probably just what the leaves do. Cannabis has a unique leaf shape and edges grow into themselves often.

Look fine keep rolling buddy