A wave-making water return device for use in an aquarium, which is constructed to have an inlet to receive water, an outlet to discharge the water into the aquarium, a fluid connection between the inlet and outlet, and an actuator to rotate the outlet so as to make waves of the water in the aquarium. The outlet is rotatable with respect to the inlet around an axis concentric with the inlet. The fluid connection includes an inner pipe coupled with the inlet and rotatably supporting an outer pipe fixed with the outlet. The outer pipe is rotated back and forth around the inner pipe by the actuator. The actuator includes a motor having a motor shaft, a first rigid arm rigidly coupled with the motor shaft, and a second rigid rod pivotally coupled with the first rigid arm and the outlet.

The present invention aims at providing a small size air pump which has a simple structure and is less likely to incur restrictions on its space for installation and accommodation. The present invention provides a small size air pump 1 in which a motor 4 is driven to actuate a pump section 3, so as to carry out a predetermined aspirating operation; the air pump 1 comprising a worm gear 15 disposed at an output shaft 4a of the motor 4; a worm wheel 16, disposed between the motor 4 and the pump section 3, meshing with the worm gear 15; a smaller gear 18 disposed coaxial with the worm wheel 16; a larger gear 20, disposed at a position held between the motor 4 and the pump section 3, meshing with the smaller gear 18; and an actuator element 21 having one end pivotally connected to a periphery of a flat part 20a of the larger gear 20 and the other end connected to an end part of a piston 5 of the pump section 3.

An aquarium water circulation system for providing improved water circulation to a saltwater aquarium by simulating a natural wave motion. The inventive device includes a container having an interior portion, a plurality of upper slots within the container, a plurality of lower slots within the container, a shaft having a first threading and a second threading, a plunger member threadably attached about the shaft and slidably positioned within the container, and a motor mechanically connected to the shaft for rotating the shaft. As the plunger member is forced downwardly, the water within the container is forced out from the lower slots and into the upper slots. When the plunger member is forced upwardly, the water within the container is forced out from the upper slots and into the lower slots simulating wave motions.

The present invention relates to a water director for distributing a surge or flow of water to one or more of a plurality of output ports, which can vary in shape, size, and number, typically for use in marine and fresh water aquariums. Water pumped through a conduit into the hermetically sealed Switching Current Water Director (SCWD), powers an internally mounted gear driven fluid motor, which turns a rotational valve, alternately opening and closing a plurality of water outlet ports. When mounted externally to an aquarium, proper placement of output nozzles, which are connected to a water conduit attached to the various SCWD outlet ports, provides the desired opposing, or switching back and fourth currents. Depending on the inlet and outlet port configuration, the SCWD can be adapted to suit many applications.

A fluid surge assembly for treating aquarium water and other fluids includes a treatment unit for receiving fluid, treating the fluid and depositing the fluid along a flow path to a body of fluid and a weir assembly disposed in the flow path between the treatment unit and the body of fluid. The weir assembly includes a lower weir blocking a portion of the flow path and an upper weir. The lower edge of the upper weir is offset from the crest of the lower weir to define a first fountain path. The crest of the upper weir defines a portion of a second fountain path. The second fountain path intersects the first fountain path to increase the velocity and distance traveled of the fluid. The invention also includes aquarium systems employing the fluid surge assembly. In some embodiments, the aquarium systems provide an opaque decorative member to block the treatment unit from view. In some embodiments, the decorative member is live rock. In preferred embodiments, a top portion of the decorative member is disposed below the first and second fountain paths to create the image that waves are crashing over rocks. In a particular embodiment, the aquarium tanks are constructed to surround the treatment unit and hide it from view from all sides of the tank.