Difference between using Zinc Nitrate instead of Potassium Nitrate for Salt Bridge Solution?

I have a lab question which asks "Suppose that before you began this experiment you ran out of your salt bridge solution of Potassium Nitrate and the only substitute available was zinc nitrate, would this have an effect on the cell potentials you measured?"


Now I'm guessing the answer is yes, since Zinc will have a different reduction potential than Potassium, but I don't understand how to explain that in regards to the actual transfer of electrons and change in Voltage measurement. Any ideas? 


\*Some background information, we used half cells of AgNO3, FeCl2, Zn(NO3)2, Ni(NO3)2, Cu(NO3)2, and measured the voltage of each combination of half-cells by connecting each to both positive and negative lead.


Thanks so much..


