The refined oils sensor works by sending a light beam into the water to be tested, at a fixed wavelength. This wavelength of light excites hydrocarbons which subsequently fluoresces at a known wavelength band. The level of excitation measured is proportional to the amount of refined oil present in the water.
To use Aquaread's refined oil sensor, first install it into your probe of choice, then perform a full calibration of the using REFOIL-CAL solution from Aquaread. Once calibrated it's good to go. Simply put the probe into the body of water, allow the reading to stabilise and take your measurement.