Listen man....You dont want it to green up during flower.... adding more nitrogen during flower will deprive bud growth... I swear to you...Yellowing dyin leaves in 6th week of flowering is perfectly normal and a good sign that your doing things right...If your plants were real green in the 6th week of flower, people would be telling you your doing something wrong...your plants are 100 % healthy by the looks of the pics bro...