Mr Aqua Porous Ceramic Rings are highly-porous media with massive surface area for bio filtration. The rings are ideal for canister filters and sumps. Made of ceramic, the rings are inert and will not affect pH. Ceramic rings are also long-lasting, can be washed and re-used. Benefits These are the benefits of using Mr Aqua Porous Ceramic Rings as bio filtration media: Each highly-porous ring has a massive surface area that promotes colonisation of beneficial bacteria Beneficial bacteria break down ammonia, nitrite, nitrate and dissolved nitrogenous compounds. This is the natural process of bio filtration Promotes fast and efficient filtration Results in clearer, cleaner water Reduces frequency of water changes significantly Suitable for fresh and saltwater aquarium Ideal for canister filters and sumps Will not affect pH levels Can wash and re-use