well i could be wrong but if you are not going to control the on and off of your fert valves with the epro i don't think switchpro is going to do you any good,unless i am missing something the best you can do with your current setup is to connect the epro to the force system and run it in automatic and try to have it match what your planter monitor,what kind of planter monitor are you running?i am running a raven crop start system,with water or fert,controlled by a epro lx,with a side kick pro for insecticide injection.