A gravel vacuum, including a pump, a detachable suction base connected to the pump to which a suction tube can be attached, a filter connected to the suction base, a return assembly, at least one valve, and an alternate flow path. The pump impels a flow of water from the suction base, through the filter, and out the return assembly. The valve permits adjustment of volume of the flow for different sizes of fish aquariums. The alternate flow path reduces back pressure on the pump when the valve is used to adjust the volume of the flow. Also, a method of using the gravel vacuum.