TURBIDIMETERS Direct-reading, 3 Range, USEPA Approved Design Orbeco-Hellige Model 966 Portable and Model 965-10A Bench-top Turbidimeters quickly and precisely measure the clarity or cloudiness of any type of fluid. Both meet the official specifications of USEPA, ASTM, Standard Methods of APHA, AWWA, WEF and other world-recognized authorities. True nephelometers, both test at the officially mandated 90 degree angle between photo-detector and incident light beam. Direct-reading displays give results in NTU''s (Nephelometric Turbidity Units) over the full span of turbidity in 3 ranges. Both meet design requirements of USEPA Method 180.1 and are ideal for NPDES and NPDWR compliance reporting. Also can be used to test water for Barium, Sulfate, Nitrate, Silver and Chloride using turbidimetric chemical analysis.