text: There are a number of chemical reagents that are available for treating turbidity. Reagents that are available for treating turbidity include aluminium sulfate or alum (Al(SO)·nHO), ferric chloride (FeCl), gypsum (CaSO·2HO), poly-aluminium chloride, long chain acrylamide-based polymers and numerous proprietary reagents. The water chemistry must be carefully considered when chemical dosing as some reagents, such as alum, will alter the pH of the water.
  The dosing process must also be considered when using reagents as the flocs may be broken apart by excessive mixing.