Agreed,agreed.....agreed.Phase out the feeders and look into getting a wet/dry sump system and keep your one canister to accompany it.In my opinion no other filter type beats the water turnover rate and bacteria surface area of a good sump system.You can also drop in the pellets at night when your cats are likely more active and hunting for food if you are not already.Id say two cannisters is not enough for your bioload at all. You might be able to get around it with a heavy waterchange schedule but only then. You should look into showerfilters or a sump with an pipeoverflow.
And IMHO id say stop feed live feeders. Get the fish on to frozen food. Once that is done you can break them to into feeding pellets.
Live feeders comes with nothing good at all.