Are you dosing
iodine ?
This might help, unless you are already using this , then if overdosed do 2 water changes per week to stabilize water chemistry.
PH is a big factor too, just check what you can all the basics first.
Don’t be scared if test showing something odd, a lot of times tests are wrong (too old, wrong storage or simply inaccurate).
So basically water change is your best friend.