@ fdd or anyone who can help. im growing ak47. ive got some grow years under my belt. every crop @ 3rd wk 12/12 i get what looks like fert burn that starts on the tip of fan leaves then proceeds along the outer edge before closing in on the middle. my response is to up the nutes listening to guy @ grow store saying its a phos def. every crop with different nutes. ive used ionic ,gh ,fish emulsion and now age old. 4 gal bucket pro mix. feed ph 6.2 2-3 Tbsp gallon age old bloom with fossil fuel ,nitrozyme, greenfuse bloom booster all at full strength every watering and when i notice the problem a little cal-mag. is that clear enough?