Why is this happening? since I’ve started growing last July I’ve had a horrible problem with my plants yellowing 3 weeks into flower. I use day old tap( to dissipate chlorine), with mills, R the first 2 weeks then c4 then pk week 7 then tap bs last week. Should I start using chicken poop in early flower? I feed water feed waterin early flower. Is it nitrogen? Over watering, over lighting? Light bleaching? I have problems with spider mites in veg but not in flower.