First off welcome
I know how fustrating it can be but let me ask you some questions ...
What kind of light do you have and what how old are the bulbs?
What are your tests NitrAtes, calcuim , Mag , etc ?
What size tank ?
What are the inhabataints ?
Perhaps we can lead you if we get a few answers ...
I know not really helpful but we can direct you in the right way ...HTH