Ensure crystal-clear water with the Oceanmax Blue Bio Sponge, size 100x100x4cm, PPI 20. This high-performance blue sponge combines mechanical and biological filtration, effectively trapping debris while fostering beneficial bacteria. The distinctive blue color makes maintenance simple, and its washable, durable material is suitable for fresh or saltwater aquariums. Choose this sponge for reliable, efficient filtration and easy system integration.