IMO filtration is one of the most misunderstood aspects of the hobby (especially when coming to canisters).
Having a can suck up debris, and storing it, without regularly cleaning it out of that can, is "not" taking those waste products out of the tank, Its just sweeping dirt under a rug. Because most cans are not user friendly to clean out, is why I consider them inferior forms of filtration.
All "bio media" is there to break down ammonia and nitrite, into "less toxic" compounds (notice the word is "less" not non) nothing else, and if the can is allowed to build up gunk, and become plugged and anoxic, this hinders that process by covering up the good biofilm, with oxygen starving stuff.
IMO it is better to vacuum out detritus and change a little water(daily) if need be, and to keep the filters from gunking up with crud.
If you test water, and ammonia and nitrite are non-detectable, your filter is functioning the way it should,