Use great care with potash. Not sure what formulation you have, but a l-i-t-t-l-e goes a LONG way!
Not even sure if that’s the prob. Di is going the complete opposite way. Not being sure what’s wrong, you might use a couple plants as guinea pigs. Try one each way—fert/no fert for a couple of days and see which one perks up or not.
Good luck!
Did just that. Used 1 teaspoon of potash in the 20 inch pots and added about the same amount of epsom salts and watered really well. Will be looking forward to see improvement in the next few days.