QUANTOFIX Multi stick for aquarium owners are the semi-quantitative test strips for the determination of the total hardness (Ca 2+ , Mg 2+ ), carbonate hardness (HCO 3 -, CO 3 2-) and the pH value of aquarium water. Measuring range: 0-6.3-12.5-18.8-25.0-31.3 °e (total hardness) 0-3.8-7.5-12.5-18.8-25.0 °e (carbonate hardness) pH 6.4-6.8-7.2-7.6-8.0-8.4