| Items | Normen |
| Uiterlijk | Wit kristallijn poeder |
| Assay (%) | 98.5 - 101.5 |
| PH | 5.5 - 6.5 |
| Verlies bij drogen (%) | Max. 0.2 |
| Residu op ontsteking (%) | Max. 0.1 |
| SO4 (ppm) | Max. 60 |
| Zware metalen (ppm) | Max. 20 |
| As (ppm) | 1 Max |
| FE (ppm) | Max. 10 |
| NH4 (ppm) | Max. 100 |