678.5 PSU = 675.1916 g/kg
| PSU | g/kg |
|---|---|
| 663.5 PSU | 660.2647 |
| 668.5 PSU | 665.2403 |
| 673.5 PSU | 670.2159 |
| 678.5 PSU | 675.1916 |
| 683.5 PSU | 680.1672 |
| 688.5 PSU | 685.1428 |
| 693.5 PSU | 690.1184 |
678.5 PSU = 675.1916 g/kg
1 g/kg ≈ 1.0049 PSU · 1 mg/L ≈ 0.001 PSU · 1 ppm ≈ 0.001 PSU (dilute aqueous approximation)