Abstract: A method and apparatus for determining the effect of various agents on the growth of biological material (biofilm), microbially-influenced corrosion and the deposition of organic and inorganic contaminants is disclosed. The method and apparatus allow for the modeling of the growth of biological contaminants and the deposition of organic and inorganic materials on industrial equipment surfaces, such as those used in the pulp and papermaking industry. The device consists of a tray which includes recessed areas for receiving coupons, as well as fluid inlets and fluid outlets for permitting the flow of liquid samples over the coupons. The design and configuration of the apparatus provides a great deal of versatility in testing various biocidal and other agents under select environmental conditions.