Patent ID: 7001509

Claim:
An aquarium filter for mounting externally of an aquarium tank, comprising: an intake chamber for receiving contaminated water from the aquarium tank; a filtering chamber in flow communication with the intake chamber, the filtering chamber including a filtration member for filtering the contaminated water to return clean water back to the aquarium tank; a partition wall disposed between the intake chamber and the filtering chamber for overflowing water from the intake chamber into the filtering chamber; an intake tube for supplying water from the aquarium tank to the intake chamber; a flow resistive, porous member disposed between the partition wall and an inner wall of the aquarium filter; and pump means having an impeller for drawing water from the aquarium filter into the intake chamber through the intake tube, wherein responsive to stopping the pump means, water in the intake chamber begins to reversely flow out of the intake chamber into the aquarium tank through the intake tube due to a siphoning action, water in the filtering chamber flows back to the intake chamber through the porous member and over the porous member if a water level of the filtering chamber is higher than that of the intake chamber, the reverse flow is faster than the water flowing into the intake chamber such that the siphoning action breaks when the water level of the intake chamber drops below that of the filtering chamber by a predetermined distance with the impeller being exposed, the water in the filtering chamber continues to flow back to the intake chamber through the porous member until the water level of the filtering chamber is equal to that of the intake chamber, and at this time a sufficient amount of water is stored in the intake chamber as priming water for a future restarting of the aquarium filter.