Concealed filtering and aerating means for fish tanks

Claim 1

A FISH TANK HAVING A BACK WALL, A FRONT WALL, END WALLS, AND A BOTTOM WALL FOR RECEIVING A LAYER OF SAND THEREON, A PARTITION WALL EXTENDING ALONG ONE OF THE WALLS WALLS, AND A BOTTOM WALL FOR RECEIVING A LAYER OF SAND PARTITION WALL HAVING A CENTRAL PORTION THEREOF SPACED FORWARDLY FORM SAID ONE WALL AND DEFINING AN OPEN TOP WATER-CONDUCTING COMPARTMENT, OPEN-ENDED PUMPING TUBE MEANS IN SAID COMPARTMENT BELOW THE LEVEL OF THE WATER IN THE MAIN PART OF THE TANK BEHIND THE PARTITION WALL, SAID PUMPING TUBE MEANS HAVING A HORIZONTALLY ARM EXTENDING FORWARDLY THROUGH THE UPPER PART OF THE PARTITION WALL ABOVE THE LEVEL OF THE WATER, AN AIR TUBE CONNECTED TO A LOWER PART OF THE PUMPING TUBE MEANS BELOW THE LEVEL OF THE WATER AND EXTENDING OVER SAID ONE WALL FOR CONNECTION TO AN EXTERNAL AIR PUMP, THE LOWER PART OF SAID PARTITION WALL HAVING APERTURES BELOW THE LEVEL OF SAID SAND AND PROVIDING LIMITED COMMUNICATION BETWEEN THE MAIN PART OF THE TANK AND SAID COMPARTMENT.