Abstract: An aquarium heater that is disposed on an outside surface of the aquarium tank for maintaining the water in the tank at a selectable temperature. The heater is preferably supported by a hanger or holder from a top edge of the tank and has a heat transfer plate disposed in intimate contact with a side or back wall of the tank. The heater includes, in addition to the heat transfer plate, a plastic or phenolic housing, a heating element, insulation and a settable thermostat contained in a temperature-sensing section of the housing. When the tank water is below a threshold temperature the thermostat closes coupling power to the heating element, which is preferably a rope-type resistance heater covered by a metal foil blanket, and when the temperature of the water reaches the threshold the thermostat temporarily opens to uncouple power to the heating element. In addition to the temperature sensing section of the housing there is also provided a heating section in which the heating element resides.

Abstract: An aquarium heater that is disposed on an outside surface of the aquarium tank for maintaining the water in the tank at a selectable temperature. The heater is preferably supported by a hanger or holder from a top edge of the tank and has a heat transfer plate disposed in intimate contact with a side or back wall of the tank. The heater includes, in addition to the heat transfer plate, a plastic or phenolic housing, a heating element, insulation and a settable thermostat contained in a temperature-sensing section of the housing. When the tank water is below a threshold temperature the thermostat closes coupling power to the heating element, which is preferably a rope-type resistance heater covered by a metal foil blanket, and when the temperature of the water reaches the threshold the thermostat temporarily opens to uncouple power to the heating element.

Abstract: An aquarium waterfall composed of a base, vertical member and cap and wherein a lift tube extends from the base to the cap. A sand reservoir is formed in the base. An air tube operatively connected to the lift tube causes water to rise in the lift tube, and the water carries sand with it from the base to the cap where the mixture of sand and water is redirected in a downward direction toward the base over outcroppings in the vertical member to simulate a waterfall.