The Hach DR/850 Colorimeter, is preprogrammed to test for 50 parameters. The DR/850 offers simple, push-button program selection and step-by-step prompts that guide users through the testing procedure. The Hach DR 850 requires the use of reagents. We can supply most of the more common reagents used in the environmental market. The instructions for each type of reagent varies and step-by-step instructions will guide the user on how to prepare the reagent, and what setting must be used with the Colorimeter for the particular target chemical being tested. The sample and reagent are mixed and put in a vial and inserted into the instrument. The Colorimeter provides a numerical value after an automatically timed period.