76-11: Amorphous Silica Scale in Cooling WatersIn 1968, most of the evaporation cooled recirculating water systems at Los Alamos Scientific Laboratory were nearly inoperable due to scale. These systems, consisting of cooling towers, evaporative water coolers, evaporative condensers, and air washers had been operated on continuous blowdown without chemical treatment. The feedwater contained 80mg & silica. A successful program of routine chemical addition in the make up water was begun. Blends of