423.5 g/kg = 425.575 PSU
| g/kg | PSU |
|---|---|
| 408.5 g/kg | 410.502 |
| 413.5 g/kg | 415.526 |
| 418.5 g/kg | 420.551 |
| 423.5 | 425.575 |
| 428.5 g/kg | 430.6 |
| 433.5 g/kg | 435.624 |
| 438.5 g/kg | 440.649 |
423.5 g/kg = 425.575 PSU
1 g/kg ≈ 1.0049 PSU · 1 mg/L ≈ 0.001 PSU · 1 ppm ≈ 0.001 PSU (dilute aqueous approximation)