Juwel Bio Plus XL Jumbo Coarse Sponge for Bioflow XL (8.0). The Juwel Bio Plus Coarse Sponge is designed to remove large to medium particles, and its design allows bacteria to thrive and multiply thanks to its large surface area. It is recommended to change the Bio Plus Coarse Sponge every 3 months to maintain filter efficiency. Suitable for Rio 400/450, Vision 450, and Trigon 350.