
| ADVANTAGES | |
|---|---|
| Naturally occurring material | |
| Low uniformity coefficient for maximum contact for controlled correction | |
| Slower reacting for controlled correction | |
| Inexpensive | |
| PHYSICAL PROPERTIES | |
| Color | Near white |
| Bulk Density | 90 lbs./cu.ft. |
| Mesh Size | 16 × 40 |
| Specific Gravity | 2.7 |
| Effective Size | 0.4 mm |
| Uniformity Coefficient | 1.5 |
| Hardness | 3.0 (Mohs scale) |
| Composition |
CaCO3, 95% min. MgCO3, 3.0% max. |
| CONDITIONS FOR OPERATION | |
| A gravel support bed is recommended | |
| Water pH range | 5.0 – 7.0 |
| Bed depth | 24 – 30 in. |
| Freeboard | 50% of bed depth |
| Backwash rate | 8 – 12 gpm/sq.ft. |
| Backwash Bed Expansion | 35% of bed depth |
| Service flow rate | 3 – 6 gpm/sq.ft. but may be modified to adapt to local conditions |