The HI3843-100 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate hypochlorite measurements with the chemical test kit. These reagents follow an iodometric titration method to determine hypochlorite concentration.

For determination of hypochlorite, a slow reaction with iodide in acidic solution occurs with the chlorine present in the sample. The amount of iodine generated is equivalent to the chlorine in the sample. The liberated iodine is then titrated with standard sodium thiosulfate solution that reduces the iodine back to iodide ions. The number of drops of titrant used to reach the visual endpoint will determine the hypochlorite as mg/L chlorine (Cl₂). These reagents are designed to be used with samples that have an expected hypochlorite range of 50 to 150 mg/L Cl₂.