Extremely porous ceramic media for efficient biological filtration. Hollow design effectively distributes water flow and allows massive colonies of beneficial bacteria to grow on and inside each ring. Great for both fresh and saltwater aquariums. FilStar Ceramic Rings are designed for use in all FilStar filters but can also be used with other canister filters. For optimum biological filtration, use 1 liter per 75 gallons of aquarium water.
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