Juwel BioPlus XL Jumbo Coarse Sponge for Bioflow XL (8.0). The Juwel BioPlus Coarse Sponge is designed to remove large to medium sized particles and within its design allows bacteria to flourish and multiply down to its large surface area. It is recommended to change the BioPlus Coarse sponge every 3 months to keep your filter running as efficient and possible. Suitable for Rio 400/450, Vision 450 & Trigon 350.