A multi-channel device includes up to three channels for optical testing of liquid samples. The liquid sample(s) may include surface water, drinking water, processed water or the like. The multi-channel device may include a turbidity channel and a color channel that measure turbidity and color, respectively, of a liquid sample using spectrographic analysis. The multi-channel device may also include a colorimetric channel that measures the concentration of various analytes in a liquid sample, such as free chlorine, total chlorine, copper and phosphate.