calibration solution customized for calibration and system testing concentration range (c: 10 - 1,000 mg/L S or N or Cl) concetration value freeley selectable element freely selectable set of 10 vials á 5 mL of standard solution and 5 vials á 5 mL of blank solution Attention, the desired concentration level and element has to be mentioned in the order. calibration solution customized for calibration and system testing concentration range (c: 10 - 1,000 mg/L S or N or Cl) concetration value freeley selectable element freely selectable set of 10 vials á 5 mL of standard solution and 5 vials á 5 mL of blank solution Attention, the desired concentration level and element has to be mentioned in the order.