The Hach digital titrator produces repeatable results through the use of concentrated titrants packaged in compact interchangeable cartridges. To titrate, simply attach a cartridge to the titrator and insert a delivery tube. Each turn of the delivery knob dispenses a calculated amount of titrant. The numerical counter records the volume. When the end point is reached, calculate the sample concentration using the number displayed on the counter. Any remaining reagent may be capped and stored for future use.