
| Item | First grade | Superior grade |
| NaHSO2·CH2O Content% | 98% min. | 99% min. |
| State of Solution | Be soluble in water and appear in clarification or micro turbidity | Be soluble in water and appear in clarification or micro turbidity |
| Sulfide | Not in dark | Not in dark |
| Alkalinity as sodium carbonate | 3.0% max. | 1.5% max. |
| Odor | Slight | Slight |
| Cu & Mn | 5ppm max. | 3ppm max. |