646.5 g/kg = 649.668 PSU
| g/kg | PSU |
|---|---|
| 631.5 g/kg | 634.594 |
| 636.5 g/kg | 639.619 |
| 641.5 g/kg | 644.643 |
| 646.5 | 649.668 |
| 651.5 g/kg | 654.692 |
| 656.5 g/kg | 659.717 |
| 661.5 g/kg | 664.741 |
646.5 g/kg = 649.668 PSU
1 g/kg ≈ 1.0049 PSU · 1 mg/L ≈ 0.001 PSU · 1 ppm ≈ 0.001 PSU (dilute aqueous approximation)