The present invention relates to a chemical feeder that includes a support plate that is positioned within the housing chamber of the chemical feeder, in which one or more extensions extend upward from an upper surface of the base plate of the support plate. The message interceptor may be operative to intercept messages transmitted by a first device over a network to a recipient. A plurality of generally parallel spaced apart recesses are formed in the lower surface. The first binary images are logically combined generating a composite image mask.