Abstract: A water filter includes a pressure switch in order to sense inlet water pressure of the water filter, a solenoid valve for controlling water inlet of the water filter, the solenoid valve is disposed after the pressure switch and is acted in response to the pressure switch. A central processing unit is coupled to the pressure switch and the solenoid valve for delaying action of the solenoid valve in response to the pressure switch. The pump is stopped when the pressure is actuated intermittently and continuously and when the pump runs over a predetermined time interval continuously.

Abstract: An aquarium including a tank disposed above a housing, a screen disposed in the housing, a space formed below the screen, a conduit coupling the tank to the housing for supplying water from the tank to the housing and to the space, an outer tube vertically disposed in the housing and an inner tube disposed in the outer tube and having a lower end extended outward of the housing. The water contained in the space is forced to flow into the outer tube and to flow out of the housing via the inner tube when water is supplied into the housing and the space from the tank.