Abstract: An aquarium filtering system for gravity flow systems wherein a float valve is incorporated in the drain conduit from the aquarium, wherein the float valve is operated by the water level of filtered water within a sump, such that if the water level in the sump rises above a predetermined level due to inadequate water return to the aquarium, the drain conduit will be closed by the float valve. A pre-filter is incorporated in the drain conduit to filter water upstream of the float valve, with the filter preferably being a sock filter enclosed in a sealed housing which remains filled with water. Most preferably, the float valve and any pumps utilized in the system are submerged within the water in the sump to reduce noise.

Abstract: An aquarium filtering system for gravity flow systems wherein a float valve is incorporated in the drain conduit from the aquarium, wherein the float valve is operated by the water level of filtered water within a sump, such that if the water level in the sump rises above a predetermined level due to inadequate water return to the aquarium, the drain conduit will be closed by the float valve. A pre-filter is incorporated in the drain conduit to filter water upstream of the float valve, with the filter preferably being a sock filter enclosed in a sealed housing which remains filled with water. Most preferably, the float valve and any pumps utilized in the system are submerged within the water in the sump to reduce noise.