621.5 g/kg = 624.545 PSU
| g/kg | PSU |
|---|---|
| 606.5 g/kg | 609.472 |
| 611.5 g/kg | 614.496 |
| 616.5 g/kg | 619.521 |
| 621.5 | 624.545 |
| 626.5 g/kg | 629.57 |
| 631.5 g/kg | 634.594 |
| 636.5 g/kg | 639.619 |
621.5 g/kg = 624.545 PSU
1 g/kg ≈ 1.0049 PSU · 1 mg/L ≈ 0.001 PSU · 1 ppm ≈ 0.001 PSU (dilute aqueous approximation)