Filtration is the heart of an aquarium. Fish needs to be crystal clear water to stay in an aquarium healthy. Filtration can be biological, mechanical and chemical. Sobo Internal Filter WP1000F is a mechanical filter. Its sponge absorbs dirt and clears the water. This is Suitable for both fresh and salt water. It is Fully submersible and ideal for any aquarium filtration. This is Super quiet, efficient energy economizing and easy to clean. This is an ideal filter for tanks up to 150 to 200-liter aquariums.