ABSTRACT
This chapter deals with important water quality parameters that serve as controlling variables, those that strongly influence the behavior of many other constituents present in the water. The major controlling variables are pH, oxidation-reduction (redox) potential, alkalinity and acidity, temperature, and total dissolved solids (TDS). This chapter also discusses several other important parameters, such as ammonia, sulfide, carbonates, dissolved metals, and dissolved oxygen (DO), which are strongly affected by changes in the controlling variables.
