Image Number 3 for United States Patent #6865771.
An apparatus for cleaning liquid-filled tanks, e.g., aquariums, includes an inner cleaning assembly which moves across the interior wall of the tank and an outer cleaning assembly which moves across the exterior wall of the tank. The inner and outer cleaning assembly are magnetically attracted to each other so that manipulation of the outer cleaning assembly results in corresponding motion of the inner cleaning assembly. The inner cleaning assembly bears a cleaning pad which moves across the tank wall to clean matter therefrom. The inner cleaning assembly is buoyant so that interruption of the magnetic engagement between the inner and outer cleaning assemblies results in the inner cleaning assembly floating to the top of the liquid-filled tank for easier retrieval. One or more accessory attachment members may be provided, each of which is removably attachable to the inner cleaning assembly, and these may bear scrapers and/or coarser or finer cleaning pads so as to allow the inner cleaning assembly to be adapted for desired cleaning operations.