Rolf C. Hagen (USA) Corp.
Rolf C. Hagen (USA) Corp.'s Fluval Moss Balls are designed to mimic Marimo balls, clusters of live filamentous green algae that help control other algae in aquariums, the company states. The non-biological balls are made with a covering that keeps the water clean by absorbing and helping to reduce many aquarium compounds that encourage odors and matter accumulation, and a core made of a special resin that absorbs and traps phosphate, nitrate and nitrite. Additionally, unlike real Marimo balls, there is no concern over Fluval's Moss Balls growing too large for the aquarium space, since they are not alive and do not grow. One ball is sufficient to clean the water of a 10- to 20-gal. aquarium, and for larger setups, aquarists may use multiple balls, the company states.