Cut your Own to fit Durable Mechanical filtration for Aquarium or Pond. Hundreds of uses that include pre-filters for wet/dry’s, sumps, canister filters, cut to fit for HOB filters, Pond prefiltration, copepod habitat, aquaponics systems, turtle tanks, terrariums and more. Used by us and thousands of aquarium hobbyist and professionals alike. Excellent Replacement pad for your fresh and salt water aquariums and sumps. Changing your media often removes the collected solids before they are broken down and prevents them being added to the system as unwanted nutrients and will increase your water quality.