A method for testing the performance of surface coatings on the formation of biofilm and encrustation on materials. The method includes, providing a plurality of material retaining sites, providing the material retaining sites with a material, wherein the material models a surface likely to be involved in biofilm formation and encrustation deposit. The method further includes the steps of providing a liquid growth medium, wherein the liquid growth medium includes at least one microorganism, the liquid growth medium arranged to cover at least a portion of the material, and incubating microorganism and encrustation on the material retaining sites in the presence of the liquid growth medium.