Ok how cool is it actually getting? I’ve had a cloner outdoors in 55 degrees.
Roots should already be seen the pics of the leaves look like a pale green and not a darker healthier green. If this is true then you need the timer I posted earlier set it for 30 seconds on 15 minutes off running like that 24 hours a day with
nutrient water that is ph checked.This will basically flush any water thats in the rockwool out and replacing it with fresh nutrient water. Whatever roots you have in the rockwool will suck up the
nutrients more often making the plant healthier.