U.S. Air Force Airman 1st Class Kristopher Richardson, 52nd Aerospace Medicine Squadron Bioenvironmental Engineering technician, uses a phenol red solution to determine pH level of tap water at Spangdahlem Air Base, Germany, January 7, 2020. A perfect pH level is 7.0 however some minor variance is allowed. A proper pH is important to prevent the water from being dirty or corrosive. (U.S. Air Force photo by Senior Airman Kyle Cope)