An embodiment provides a method for measuring aluminum concentration in an aqueous sample, including: preparing a chromeazurol S indicator solution; placing the chromeazurol S indicator solution in a sample containing aluminum, wherein the placing causes the chromeazurol S to chelate aluminum within the sample creating a colored complex; and measuring, using colorimetric techniques, a concentration of aluminum within the sample, wherein the measuring comprises measuring an absorbance at a wavelength for the colored complex. Other embodiments are described and claimed.