A circular array of light-emitting diodes provide the excitation light for the chlorophyll-a turbidity backscatter sensors. Optical filters in front of the optical receivers then separate the backscattered light from the fluorescence signals. The filter also prevents the influence of solar light on the measurements. A wiper sweeps the optical surface before each sample to remove dirt and residue, improving the repeatability of measurements. The turbidity sensor has a superior stability in low concentration areas and the correlation with the suspended sediment in high concentration areas has been improved. The instrument can therefore be used in river and dam applications, as well as in the marine field. The Infinity CLW is controlled through the RS232-C port of a PC. The basic measurement set-up requires only the selection of the start time and sampling interval. After deployment, information such as measurement start time and calibration coefficients are easily transferred, along with the measured data.