Total Hardness Reagent Set measures high range total hardness in water, wastewater, seawater, oil and gas field waters by EDTA Titration.
Total Hardness Reagent Set measures total hardness in the range from 100 to 4000 mg/L as CaCO₃ in water, wastewater, seawater and in the range between 100 and 200,000 mg/L as CaCO₃ in oil and gas field waters. Article 2448100 uses EDTA Titration method (8213, 10247). The product can be used to conduct 100 tests.
Total Hardness Reagent Set includes:
- ManVer 2 Hardness Indicator Powder Pillows (p/n 85199)
- Hardness 1 Buffer Solution (p/n 42432)
- EDTA Digital Titrator Cartridge, 0.800 M (p/n 1439901)
Before starting analysis:
- It is recommended to use TitraStir Titration Stand to hold the Digital Titrator and stir the sample.
- It is necessary to adjust the pH to 7 with sodium hydroxide solution before analysis of the collected sample.
- It is required to correct testing results for the dilution caused by the volume additions.
Procedure for CaCO₃ evaluation
Firstly, select the appropriate sample volume, choose the titration cartridge and attach to the Digital Titrator. Secondly, fill 250mL Erlenmeyer flask with the sample, pipet 2mL of Hardness 1 Buffer Solution and swirl to mix. Thirdly, pour ManVer 2 Hardness Indicator Powder Pillow and swirl the content of the Erlenmeyer flask. Finally, add titrant until the color changes from red to pure blue and calculate the concentration.
Summary of method
Buffer solution adjusts the pH to 10.1. An organic dye, calmagite, is test indicator that enters into reaction with calcium and magnesium ions giving red complex. The EDTA titrant reacts with all of the free calcium, magnesium, barium and strontium ions. After the EDTA has reacted with all of the free magnesium ions, the EDTA removes the magnesium ions from the indicator. After that the indicator color changes from red to blue.
Sample preparation
Adjust the sample pH to 2 or less using concentrated nitric acid to conserve the sample. Store the conserved water, wastewater or seawater sample at or below 6 °C (43 °F) for a maximum of 7 days. Keep the preserved oil and gas field water sample at room temperature for up to 6 months.
| Brand | Hach |
| Measuring range | 100-4000 mg/L CaCO₃ |
| Measuring range (2): | 100-200,000 mg/L CaCO₃ |
| Method | EDTA Titration method |
| Standard method | 8213, 10247 |
| Number of tests | 100 tests |
