This study calculated coefficients for the model elaborated by Hasan Ali San in 1989 based on the percentage of flocculated particles removed by three coagulants commonly used for water purification. The coagulants used were type A aluminum sulfate, type B aluminum sulfate and ferric chloride. An experiment was designed to study water with initial turbidity between 25 and 30 Nephelometric Turbidity Units (NTU). The experiment consisted of filling a sedimentation column with water and colloid particles which were agitated rapidly and then slowly with compressed air. This allowed the percentage of particles removed from the remaining turbidity to be determined at different times and different depths by measuring sedimentation of the flocculated particles. Once percentages of material removed had been calculated, an isoconcentration graph was elaborated and multiple linear regression was used to determine the coefficients of the model proposed by San.