This is the Pollen Glass with a wider diffusion filter, which is placed on the side panel of aquarium. Its unique J-shape glass pipe design sits elegantly inside the aquarium tank. 20 is designed for 60cm tank with fully grown sun plants, such as Riccia that requires much CO2 and 30 diffuses CO2 effectively for 75-90cm tank. Pollen Glass Large is made of glass including J-shape parts. Careful handling is required when attaching or detaching suction cup.

20 for CO2