Aqueous solution constituent analyzer

Technology is provided for an aqueous solution constituent analyzer. The analyzer includes an ultraviolet light emitting diode (LED) with a current source providing variable current thereto. A spectrometer is positioned for receiving light from the LED transmitted through an aqueous solution. A controller receives radiant flux data for a plurality of wavelengths and determines, based on the radiant flux data, a usable number of the plurality of wavelengths that satisfies a relative uncertainty threshold. The controller can increase the current to the LED if the usable number of wavelengths is less than a minimum threshold and calculate a concentration of a constituent of interest in the solution. The controller can also determine a peak wavelength of the plurality of wavelengths having the greatest intensity value, and decrease the current level to the LED if the peak wavelength has an intensity value greater than a saturation value for the spectrometer.