Is there general guidance for creating the most accurate calibration curve for suspended solids?
TSS portable suspended solids curve recommendations
Hach recommends selecting a calibration point with a value in the upper third of the range expected. Start with a single point calibration in that range. In case a single point calibration is not sufficient, the error "message Calibration insufficient" or "Calibration insufficient +" will guide you to set up an appropriate curve, thus will provide a more accurate measurement.