Sorting or searching by Universe

Hi everyone, I'm working with ACS 2013 5-year estimates at the census tract level. I am wondering if there is a way to search the FactFinder by Universe and, if so, how that can be done? I would like to create ratios using raw numbers that I'm finding in FactFinder tables, however, these come from different Universes (ie, the numerator I want to use is drawn from the "Civilian noninstitutionalized population" Universe, and the denominator I want to use is drawn from "Families"). Any thoughts, comments, or suggestions are appreciated! Thank you.