Control of struvite formation can be obtained by minimizing the concentration levels of any of the three main soluble ions.  By complexing the orthophosphate ion with a trivalent metal such as ferric iron (Fe⁺³) or aluminum (Al⁺³), the precipitation of metal orthophosphate will reduce the soluble phosphorus levels in wastewater, thus lowering the potential for struvite crystallization.  These precipitation reactions are as follows:

1)  Fe⁺³  +  PO₄^-3  →  FePO_{4 (solid)}

2)  Al⁺³  +  PO₄^-3  →  AlPO_{4 (solid)}

Ferric and aluminum salts include ferric sulfate, ferric chloride, aluminum sulfate, and aluminum chloride, typically available as liquid solutions.  Aluminum salts are the most efficient at orthophosphate removal based on the weight of aluminum metal needed to remove soluble phosphorus.  The efficiency of these reactions depends on pH, uniform mixing during chemical addition, and in the case of ferric iron, the oxygen level in the wastewater.