This chapter evaluated a spectrum of chemical restoration approaches of eutrophic water systems, highlighting the key role of internal nutrient loads to guide remediation methods that control eutrophication. The usage of P- and joint P-/N-inactivation agents have been considered as feasible restoration tools through capacity and application methods in alignment with a wide spectrum of individually-examined nature-contexts, including that of water quality, algal blooms, flora, and fauna. Moreover, an integrated approach was developed to evaluate those restoration tools of degraded waters through specified conditions when P-inactivation agent was applied.