Store sodium hypochlorite solution away from heat and light to prevent decomposition, such as in polyethylene tanks vented to release oxygen. Provide containment basins. Avoid use of stainless steel in storage or handling. If dilution is required prior to treatment, use only deionized or distilled water.
The standard industrial strength 12 percent solution of sodium hypochlorite can precipitate calcium carbonate (CaCO3) where raw water contains high levels of calcium. Allow for this by avoiding small-diameter piping, etc.
To monitor residual chlorine, most agencies and industries analyze for chlorine using automatic on-line or laboratory testing based on the amperometric (electrochemical) titration method with detection in the range of 2 to 5 ppb. However, a number of compounds regularly present in water can interfere with detection. Colorimetric (spectrophotometric) and potentiometric (electrode-based) analyses are also available. Claudi and Mackie (1994) provide details and further references.