Standard Solution 5 components: 100mg/l each of Ammonium (NH4+) Magnesium (Mg 2+) Calcium (Ca 2+) Sodium (Na+) Potassium (K+) in Water CRM, ISO 17034 and ISO 17025 Conservation 36 months. (12 months after opening) Store under normal laborator 1 * 100 mL