Patent ID: 7934706

Claim:
A diffuser for use in a water filled tank comprising: a predetermined length of flexible tubular porous hose, the hose having a hollow tubular interior space and a gas permeable wall adapted to allow gas to escape from the interior space through the wall, said gas permeable wall having a substantially uniform porosity along the length of said hose provided by a plurality of micropores having an average diameter of from about 0.001 inch to about 0.01 inch of thermoset polymer particles and thermoplastic binder in a minor amount thereby bonding said polymer particles; a fitting suitable for attaching said hose to an air supply, the fitting disposed at one end of said hose; a closed end fitting disposed at the other end of the hose; and a rigid elongated ballast element freely disposed within the hollow tubular space and not connected to the fittings to provide an unoccupied portion of the tubular cross section of the hose for airflow therethrough.