This is your problem.
Thats a little less than 'suggested by the seller' level, for a full sized plant.
You are not as interested in BUYING as much nutes as they are in selling it, and you care more about your plant surviving....
Don't get me wrong, I still use AN, and don't dislike it.... but knock them nutes way the fuck down.... Get a PPM/EC meter, and use it daily. (Ph too, fucking log that shit in a notebook next to the plant! Track water temps too! The more you know, the better you grow!)
If you are over 500ppm on a plant less than 2 feet tall off the bucket.... you are over feeding. Thats with adding calmag to amend RO water.
Lots of air bubbles, and a splash of Orca (or hydroguard I assume) and life is way easier..... Never ever follow advanced nutrients schedule, its insane...
(Also, if u are using the full line.... drop piranha/tarantula/voodoo juice/nirvana, and just get a bottle of Orca.... and remember that shit is potent. Silica blast is cheaper than rhino skin..... but thinner...)
As the leaves get spotty, then the spots grow and spread... don't try to fight them. They will continue to fail, and you will go nuts trying to solve a problem thats not there. When the leaves get nasty n crispy to the point they are making more shade than they are absorbing light, clip 'em. Brown/damaged roots don't repair, must be replaced, so if there is damage, expect a delay in growth, and don't panic when it happens.....
Kinda like homebrewing man, set up a fresh bucket with the right values, then relax, and (instead of drink a homebrew) smoke a bowl.....