A fluid identification assembly is provided to determine the presence or absence of multiple components within a fluid in a conduit. The assembly includes a light source and a light detector positioned to receive a portion of light from the light source reflected by the conduit and fluid. A dual-band bandpass filter may be associated with the light detector to allow multiple wavelengths of light to be monitored, thereby monitoring the composition of the fluid based on the amount of light of each wavelength absorbed by the fluid. Rather than a dual-band bandpass filter, a second light detector may be provided, along with a beam splitter to separate light from a single source for receipt of light of different wavelengths by the light detectors. The dual-band bandpass filter may also be replaced by a second light source and detector pair for analyzing fluid using multiple wavelengths of light.
