need help to cure this plant

i got a 5 week old stich's love potion, the thing is she has some problems, her leaves seems to dry out and she slowed down the vertical growth.

its growing in a rich soil and it has just gotten water from an natural spring, no nuts at all to this point,

got 3 CFL light bulbs 2700k going 24/7, watering 2-3 times a week. temp is never below 20 celsius and never above 30

i got 2 love potion and 2 lemon haze auto, the thing is only this plant is sick, the 3 others seem ok to me (exept one leaf on the one lemon haze auto)

so what seems to be the problem and how could i fix it?

this is the lemon haze auto, whats wrong here?

i think it might time to hit um with the nutrient at 1/4 strength ,have you been adding cal mag with your water