ISO/TS 15923-2:2017 specifies methods for the automatic determination of chromium(VI), fluoride, total alkalinity, total hardness, calcium, magnesium, iron, iron(II), manganese and aluminium with photometric determination using a discrete analysis system. The field of application is water (ground, potable, surface, waste, eluates and boiler water). The method can also be applied to marine waters with matrix matching of standard and control solutions. Note that some parameters, notably iron, manganese and aluminium and possibly chromium(VI), calcium and magnesium may not be completely quantified if the sample contains particulates. Samples can be digested in acid, as long as the buffering capacity of the reaction mixture is not exceeded. Such procedures are beyond the scope of ISO/TS 15923-2:2017, which is best suited to the determination of dissolved metals following on-site filtration.