It wont just poof be healthy over night..
This is a fix step by step process..
First address the watering habits, this is very crutial.
You should not be flooding these pots or watering when they dont need it..
There are 2 ways you can do this.
By lifting pots and going based on dry weight to how much it weighs when its watered, this will tell you when to water..
You can also get a portable hygrometer and put it in the pot, watch the rh%, as it drops below 30% then water lightly..
When feeding, it's best to start with 1/2 the recommended doses.