Cotton Sponge ( white )

A white biochemical cotton filter pad, or aquarium sponge, is a porous filtration media designed to trap debris (mechanical filtration) and provide a large surface area for beneficial bacteria to grow and break down waste (biological filtration). It's a durable, reusable, and cut-to-size foam that promotes clear, healthy water in freshwater and saltwater aquariums, fish ponds, and filter systems.