A sump filter is a type of mechanical filtration device that is typically used in aquariums. The sump filter is placed underneath the aquarium, and water is pumped from the tank into the filter where it is then returned to the tank.
Sump filters are effective at removing large particles of debris and waste from the water, which helps to keep the water clean and clear. They also help to create a more stable environment for your fish by providing better filtration and aeration.