Beetle Diffuser 27mm The 30 mm glass Beetle Diffuser is a pollen style CO₂ diffuser that connects to CO₂ injection systems to easily disperse CO₂ gas into the planted aquarium. The large surface area of the 27 mm disc allows for the diffusion of large volumes of CO₂ gas, making the 27 mm Beetle Diffuser an excellent choice for mid-sized aquaria or higher-growth aquaria.   Beetle Diffuser 30mm The 30 mm glass Beetle Diffuser is a pollen style CO₂ diffuser that connects to CO₂ injection systems to easily disperse CO₂ gas into the planted aquarium. The large surface area of the 30 mm disc allows for the diffusion of large volumes of CO₂ gas, making the 30 mm Beetle Diffuser an excellent choice for larger aquaria or high-growth aquaria.   Bubble diffuser 17mm The Bubble Counting Diffuser is a pollen style CO₂ diffuser that connects to CO₂ injection systems to easily disperse CO₂ gas into the planted aquarium. The built-in bubble counter allows for easy monitoring of the rate of CO₂ injection. The inclusion of a bubble counter in the diffuser makes the use of a bubble counter on the CO₂ tank or in-line unnecessary. The Bubble Counting Diffuser has a 17 mm disc.   Slanted Diffuser The Slanted Diffuser is a pollen style CO₂ diffuser that connects to CO₂ injection systems to easily and uniquely disperse CO₂ gas into the planted aquarium. The elegant and low profile design of the slanted diffuser makes it ideal to minimize the visibility and intrusiveness of the CO₂ injection system on planted tanks. The Slanted Diffuser has a 15 mm disc.