257.5 g/kg = 258.762 PSU
| g/kg | PSU |
|---|---|
| 242.5 g/kg | 243.688 |
| 247.5 g/kg | 248.713 |
| 252.5 g/kg | 253.737 |
| 257.5 | 258.762 |
| 262.5 g/kg | 263.786 |
| 267.5 g/kg | 268.811 |
| 272.5 g/kg | 273.835 |
257.5 g/kg = 258.762 PSU
1 g/kg ≈ 1.0049 PSU · 1 mg/L ≈ 0.001 PSU · 1 ppm ≈ 0.001 PSU (dilute aqueous approximation)