So the white tips are the start of nutrient burn , So my suggestion is this slow up on the nutrients not the strength but the amount being fed to the plant . So instead of doing it every watering do it every 2nd or 3rd watering . Your PH level seems to be on point your not going to get any lock outs like this so the plant will be able to absorb all the nutrients it needs . The one thing I'm noticing is browning spots on your leafs this is caused from late stages of CalMag deficiency as well as Phosphorus . I would remove those leafs affected to avoid any unwanted trouble makers (Spider mites , Russet Mites , Scale) and I would up the dosages of both so that this slow's and eventually stops ,because your just flipping the lights its essential that you boost the PK this will facilitate the development of buds and new bud sites . All and all your pretty much on point you just need to correct a few minor things and you will be rocking and rolling ! I hope this information helps you -Happy Growing!