Check the listing for details. AQUANEAT® Replacement Canister Filter Pad SUNSUN HW-304B/404B/704B/3000. Condition: New. Listed at 18.99 USD. FEATURES: Fit for SUNSUN Canister filters HW-304B/404B/704B, HW-3000, Polar Aurora 525gph.4x sponge bio filter pads (1xCoarse, 2xMedium, 1xFine): trap most visible debris particles without restricting water flow. (Reusable after rinsed).Serve as host for the beneficial bacteria colonies. 12 pcs of white floss pads: Filter out fine particles providing crystal clear water. Provides both mechanical and biological filtration DIMENSION: 8.5” (L) x 8.5” (W) x 0.75” (H) INCLUDES: 1x coarse (Blue)2x medium (Green) 1x fine (Black) 12x floss filter pads (White) Tips for Usage and Maintenance: · Maintenance of Sponges: The sponge will need to be rinsed every time it becomes dirty, about once every 1 to 4 weeks. It’s helpful to reserve the beneficial bacteria by washing the sponge gently with water from the fish tank instead of tap water. After 6 to 12 months’ usage, the micro holes of sponge is gradually clogged by the tiny debris, the beneficial bacteria won’t have as much living space as before. That’s when the sponge filter starts to lose its efficiency. So it is also recommended to replace the sponge once 6 to 12 months or when the sponge gets worn out.