How long has it been since you cleaned the filter media? If you clean it frequently and use unconditioned tap water you are killing beneficial bacteria (BB) needed to make the waste convert so it is harmless.
If you haven't cleaned it in a while, them maybe you should. ONLY rinse the filter media in old tank water or conditioned/treated water to preserve as much BB as possible.
Possibly reduce feedings to half of the amount you normally feed each time and see if the numbers go down. Most people over feed the fish.
If your numbers start coming into line, then maybe you are over feeding.
Also check what kind of food you are using. Some have lots of fillers. Which don't do your fish or tank water any favors. Some better quality ones, I use Hikari, others like Spectrum, Omega One I think it is called.
Also do you vacuum the substrate when you do pwc
, sucking out excess food and waste at the bottom. Also helpful!
Hope that helps.
Clean conditioned water/pwc
is good to back in the right numbers.