Please update the "my info" area of your profile and include information on your setup to include such things as lighting, filtration, size, substarte, inhabitants and how long it has been running ffeding schedule etc. This way we can better help without asking a lot of questions.
First thing I would do is check all water parameters focusing on nitrate and phosphates. Then do PWC
as mentioned above. make sure your water sourse is clean such as RO
. If using tap test that as well.
Possibly cut back on feedings. It sounds like you may have a HOB
filter with a bio wheel which could be contributing to your problem.
Do you use a skimmer?
Answer these questions and update your profile and we can better help.