The fundamental objective of the authors' continuing research in this area is to increase our understanding of the chemical structures of natural product organic molecules responsible for color in natural water and the mechanism of their interaction with salts of Al3+ and Fe3+. Previous research has resulted in the isolation and identification of seven aromatic oxidation products of the parent color producing macromolecules. In this paper the research results of interaction studies using model flavonoid compounds and controlled concentrations of coagulant metal ions, alkalinity, and ionic strength are presented.