Calcite build-up in drilling fluids and in water treatment processes causes scaling problems. Data from Fann Calcimeters can help determine the proper chemical treatment. These instruments comply with the ASTM D 4373-84 Standard Test Method For Calcium Carbonate Content In Soils. This test method is under the jurisdiction of ASTM Committee D-18 on Soil and Rock and is the direct responsibility of Subcommittee D-18.13 on Marine Geotechnics. Calcimeters can determine, quickly and with a high degree of accuracy, if the scale build-up is composed of calcium carbonate. Calcimeters are suited to a differential measure of the calcite to dolomite content of the unknown sample. The Recording Calcimeter, Model 43210 records its results directly to a strip chart, leaving the operator free to perform other duties. The calcite contents are available in a matter of seconds and the dolomites can be determined in 15-20 minutes