search for uncle bens guide to 2 or 4 main tops.
never remove fan leaves if you don't have to
and the amount of soil that's there will last you probably 2-4 more weeks, so you can quit feeding for 2 more weeks, then do half of that dosage what you tried first, and work your way up.
when looking at the feeding schedule try reducing it more than you already did, but somewhat copying the schedule ratio and changes
also FFOF is buffered powdered oyster shell and I'm not sure if it has any lime in it
for this reason you should use happy frog because it uses strictly lime, and i found when i used straight ffof the oyster shell PH buffer wore off(early flower). The remaining unbuffered nutrients brought the ph of any water going into it at 5.4 or so.
i fixed it by running a lot of water slowly through it until it came out at the same ph as the water that was going in. From here i dosed nutes then pH'd the water I finished the plants off but they were stunted a little by the damage.