Provided are a method and apparatus for removing show-through of a scanned image. The transistor is a field-effect transistor having an electrically isolated gate that controls electrical conduction between source regions and drain regions. A controller is located remotely from the engine and provides the control device with an initial control amount to apply to the adjustment device. Methods of making zirconium basic carbonate are further described which involve titrating an aqueous slurry of sodium zirconium carbonate to a pH of from about 3. The method comprises at least one of said plurality of anomaly management agents receiving a message containing information related to the interaction with the referred agent from the referring agent. A switch is supported by the housing and is configured to detect water at a predetermined level within the reservoir.