Calibration Standard HI 721 Checker HC ®

Range 0:00 to 2:50 ppm | USEPA Method 330.5 / DPD | Resolution 0.01ppm

The HI 764 Checker®HC is extremely simple to use. First, zero the instrument with your water sample. Next, add the reagent. Last, place the vial into the HI 764 Checker®HC, press the button and read the results. It’s that easy.

Range 0 - 20 ppm | ESPA method | Resolution 0.1ppm

The HI 761 uses an adaptation of the USEPA method 330.5. The reaction between the chlorine and DPD reagent causes a pink tint in the sample.