The Tropica CO2 Diffuser is a small and elegant diffuser that creates a fine mist of bubbles.The fine mist is essential to ensure a good use of the CO2 gas in the water. The number of CO2 bubbles per minute can be observed and counted in the chamber under the ceramic disc, making it easy to assess how much CO2 is currently being added to the aquarium. The CO2 Diffuser is made of acrylic and a special ceramic membrane.We recommend soaking the CO2 Diffuser in water 24 hours before use to ensure fine mist formation from the start. Included is a transparent, bent tube for the transition of the CO2 hose at the edge of the pool and two sturdy suction holders for attaching the Tropica CO2 Diffuser. The Tropica CO2 Diffuser can be used for both smaller and larger aquariums.