We appreciate you buying our products. Our filter pads fit all sorts of filters and here is a diagram that shows the proper layering of how to put our filter media into your Fluval filters. For most of our filter pads, they need to be changed monthly and best rinsed every two weeks. If you are using a polishing pad they can clog up quickly depending on how much debris is in the Aquarium, they need to be rinsed much more often.
 
Hope this helps,
Lexi M
Customer service
Aquatic Experts