Bro, even if you fed your fish in an every other day basis, big cichlids poo a lot and the waste go to the filters, I dont get you guys what you mean?.....leaving a canister too much time without serviece would eventually lead to it becoming a nitrate factory, after one year I asure you it will, although Im sure it would happen much before.
Then how do you explain how my nitrates are 20 ppm in my 75g with a 16 inch jag thats has a fluval 405 that hasnt been cleaned in over than a year?
If you cant comprehend you remove waste the waste during gravel vacs/waterchanges and it doesnt all get caked into the filter then I'm at a loss of words for you.