I planted these seeds (cali og kush/haze) and 2 days after they sprouted the stems and the leaves on one of them have since turned purple. This is my first grow and it's in coco and i know there isnt any nutrients in coco. And ive heard purple stems can be caused from a phosphorus deficiency. But not this early into a seedlings life? So far all ive done is water with 5.8 ph water about 20 ml a day. Im growing in a 4 x 2 x 5 tent, with a 400 watt led light. The temp is about 19 c at lights off and 24 lights on with 60 % humidity. Is it to cold at lights off or should i not worry about it?