Suction screens are provided as the primary protection against the intrusion of marine invertebrate into a water supply system. Pump suction screens and even pump components constructed of copper or brass tends to promote less aquatic growth. Where screens are fitted, they will have to be periodically inspected and cleaned. Pump intake piping made of fiberglass materials prevents organisms from securing an attachment point. Protective coatings make it difficult for organisms to attach themselves to the surface of the equipment. These screens can be used for oil, chemicals and water. They are made of tough glass-filled nylon and stainless steel, and mount on 3/8 to 3 inch threaded pipe.