They say the upper media basket which is odd because the fx5 says the bottom but the water flow is different in them,
Fluval Water Polishing Pads are uniquely designed to fit Fluval Canister Filters. These extra thick micro-fine polyester pads effectively trap micro particles and debris as water passes through. Fluval Water Polishing Pads are ideally used when cloudy water occurs or after tank maintenance, and they fit in the upper media basket of your Fluval 305/405 Filter.
125 Gallon Cichlid tank
NEW PEACOCK BASS !!!!