I know I’m stupid Look at the pictures the OP posted and then look up cannabis nutrients problems pics via google, It's not an "major assumption" .....
It's a general diagnosis that is easily seen via pic comparisons ..... And no I'm not telling you exactly which one(s) it is...... That's the problem with these forums is that everybody just wants it spelled out cause they dont want to do the oh so hard work of reading 2 paragraphs and comparing a pic to another.... There are several people here saying the same general thing who have been here for years (2011 here) telling you whats up...
And P.S. elements dont cause lockout , PH is in control of that department..... The nutrients are just a visual sign of the symptom of the real problem, figure it out and work backwards to clear the real problem...... It's not that hard and I have faith
I know I’m stupid Ok, I am quite aware the plant is in bloom, you did provide pics remember ? My advice comes from experience , both personal and community via my local area which is ongoing and had been since before MMJ was legal in MI..... There were no "feelings" ascertained in my above statement , I don't know where you are getting that from unless I hit you're feel bads and in which case I'm sorry you're taking it that way. The plant threw flags before it got that bad for at least 2 weeks telling you that you needed to change something in it's diet and you either neglected to do anything about it .... Or you're ignorant to the signs which is totally ok as you have to learn somehow ......
Either way you're plant is too far gone in bloom to worry about it now, more hours to the dark schedule is doing nothing but further killing you're already depleted yield ... Keep using FF nutrients if ya want to after this grow , it's your grow after all lol