657.5 g/kg = 660.722 PSU
| g/kg | PSU |
|---|---|
| 642.5 g/kg | 645.648 |
| 647.5 g/kg | 650.673 |
| 652.5 g/kg | 655.697 |
| 657.5 | 660.722 |
| 662.5 g/kg | 665.746 |
| 667.5 g/kg | 670.771 |
| 672.5 g/kg | 675.795 |
657.5 g/kg = 660.722 PSU
1 g/kg ≈ 1.0049 PSU · 1 mg/L ≈ 0.001 PSU · 1 ppm ≈ 0.001 PSU (dilute aqueous approximation)