Method and system for controlling corrosion inhibitor feed

A water system comprising:

• at least one conduit through which a water stream flows;
• an injection apparatus configured to inject corrosion inhibitor into the water stream, and
• one or more processors configured to:
• determine a calcium phosphate saturation index of the water stream;
• determine at least one other parameter of the water stream;
• determine a dosage of a corrosion inhibitor composition based on a relationship between:
• (i) the dosage and (ii) the calcium phosphate saturation index and the at least one other parameter;
• and
• send control signals to the injection apparatus to administer the determined dosage of corrosion inhibitor composition to the water stream.