For saline COD samples with Chloride concentrations up to 20,000 mg/L Cl-! COD TNTplus chemistry and your Hach spectrophotometer are engineered to simplify water analysis for accurate results, everytime. For photometric determination of low range COD by the reactor digestion method. High Chloride concentrations usually interfere COD testing and lead to a high bias. Samples with low COD cannot simply be diluted since the COD detection limit is crucial. TNT815 is a safe, reliable and very easy to use method for the photometric detection of low range COD in saltwater samples, e.g. in seawater. The Direct Read Technology will provide your COD result to the nearest mg/L! No more cleaning glassware and dealing with large amounts of hazardous reagents and waste. Ideal to combine with our ezCOD recycling service!25 COD vials per box.