Calibration of TCS3200

I need to read RGB values of a colored water strip of 3 wells using TCS320. I need to use 3 of these senosrs selecting them using Multiplexer. Each sensor is giving RGB values for same red strip in different ranges in same ambient conditions. For instance, sensor 1 is giving values of RGB around 5000's , sensor 2 is giving around 10,000's , sensor 3 is giving around 20,000's. I need to calibrate these sensors for precision in values. Can any one shed light on how to calibrate multiple sensors relative to each other? Is there any arduino code for finding calibration factors of senosrs, so that I need not reinvent anything?

Thanks in advance!!