An aquarium filtering system for gravity flow systems wherein a float valve is incorporated in the drain conduit from the aquarium, wherein the float valve is operated by the water level of filtered water within a sump, such that if the water level in the sump rises above a predetermined level due to inadequate water return to the aquarium, the drain conduit will be closed by the float valve. The carrier gas and the indicator or marker component are injected in an area between the inner and outer weld of a terminal flange welded to a tubular pipe section or casing. The bead filler is cured, after being turned up about the bead, to connect the two opposite ends of the first elastomer ring, while at the same time eliminating the air trapped inside the turn-up of the body ply. The separate linear encoder further includes a display device that displays a plurality of yaw angles and the signal strengths corresponding to the respective yaw angles. To perform the classification, the object oriented image data to be rendered is received and classified and assigned as one of a plurality of possible first level object types. Thus, a prayer journal that can be reviewed periodically is maintained.