Gravel cleaner for aquariums

Claim 1

FOR USE IN AN AQUARIUM TANK HAVING A PARTICULATE BED AND CONTAINING WATER, A WATER-TREATING MEANS COMPRISING A HOLLOW BASE MEMBER HAVING AN OPEN LOWER END ADAPTED TO BE SEATED IN THE BED IN THE TANK, A SUBSTANTIALLY VERTICAL AIR TUBE EXTENDING AIR-TIGHTLY INTO THE BASE MEMBER AND TERMINATING IN AN OPEN LOWER END DISPOSED WITHIN THE INTERIOR OF THE BASE MEMBER ABOVE THE LOWER END THEREOF AND THORUGH WHICH AIR UNDER PRESSURE IS ADAPTED TO BE PASSED DIRECTLY INTO THE BED UNDERLYING THE LOWER END OF THE BASE MEMBER TO AGITATE THE BED AND DISLODGE IMPURITIES THEREFROM AND TO CREATE A VACUUM IN THE INTERIOR OF THE BASE MEMBER, SAID BASE MEMBER BEING FORMED ABOVE THE LOWER END OF THE AIR TUBE WITH APERTURES TO PERMIT WATER TO ENTER INTO THE INTERIOR OF THE BASE MEMBER UNDER THE VACUUM CONDITIONS EXISTING THEREIN, SAID BASE MEMBER HAVING AN OPENING PROVIDED ABOVE THE APERTURES THROUGH WHICH THE WATER IN THE INTERIOR OF THE BASE MEMBER CAN RETURN BACK INTO THE TANK AND FILTERING MEANS CONNECTED TO THE OPENING TO ENTRAP THE IMPURITIES AS THE WATER LEAVES THE TANK THROUGH THE OPENING, SAID FILTERING MEANS INCLUDING A TUBULAR MEMBER CONNECTED TO THE OPENING AND TERMINATING IN AN OUTER OUTLET AND DISPOSED WITHIN THE WATER IN THE TANK AND A POROUS, DISPLACEABLE BAG-LIKE ELEMENT REMOVABLY SECURED ON THE OUTER END OF THE TUBULAR MEMBER AND SUBMERGED WITHIN THE WATER IN THE TANK.