Features: 1.Thickening biochemical filter sponge, tough and durable 2.Has the best effect on decomposing the excrement and the forage leftover, can be used in sea water tank, fresh water tank and aqua-plant tank 3.Good shading features, can reduce the algae breeding 4.Multi-porous feature will avoid blockages and provide the largest adhesion area for bacteria, so as to cultivate high density nitrifying bacteria 5.Can be cut any sizes as your needed, and can be used repeatedly after cleaning, extremely convenient Specification: Description: This fish tank biochemical filter sponge can be used in sea water tank and fresh water tank. It has the best effect on decomposing the excrement and the forage leftover. Its multi-porous feature will avoid blockages and provide the largest adhesion area for bacteria, so as to cultivate high density nitrifying bacteria. Just bring it home now! Features: 1. Thickening biochemical filter sponge, tough and durable. 2. Has the best effect on decomposing the excrement and the forage leftover, can be used in sea water tank, fresh water tank and aqua-plant tank. 3. Good shading features, can reduce the algae breeding. 4. Multi-porous feature will avoid blockages and provide the largest adhesion area for bacteria, so as to cultivate high density nitrifying bacteria. 5. Strong filterability, can stable water quality and reduce fish died. 6. Can be cut any sizes as your needed, and can be used repeatedly after cleaning, extremely convenient. Specifications: Material: Sponge Color: Black Optional Size: 50 x 50 x 2cm / 19.7" x 19.7" x 0.8" 50 x 50 x 4cm / 19.7" x 19.7"x 1.6" Package Included: 1 x Filter Biochemical Sponge Pad