The operator simply sits the closed tool on the top of the top layer of filter media prior to the start of a mild backwash flow cycle.
As the flowrate increases, the tool will settle under its own weight to the top of the filter underdrain (or to the top of the gravel layer in systems that do not have a gravel-less design). At this flowrate the filter media is slightly fluidized. The operator then simply turns the top handle on the Filter Judge one half of a turn, which causes the slots on the inside tube to line up with the slots on the outside of the tool.
The media then falls into the tool, and the operator simply turns the handle on the top of the tool another half of a turn to close the tool and capture the sample.
The tool is then pulled from the filter cell. The water in the sample drains from the annular space between the inside and outside tubes. The tool is then layed on a horizontal surface where the operator once again turns the top handle one half of a turn.
The captured media is then exposed, and measurements of the captured media can be made with the handy waterproof ruler attached to the side of the slotted bottom section.
The presence or absence of mudballs can be noted, as well as the depth of the interface zone between layers of media.
The operator can pull out the media for testing, or can return the media to the filter cell.
This process is repeated throughout the filter cell until the operator is satisfied with the results.