top off project


New member
Hello fellas need to pick a brain or two here

I am putting together a top off unit for multiple tanks this unit will take care of three tanks in two different homes. I have a good pump 120v and all the plumbing needed.
But what I have been thinking was to use a float valve in each tank to turn water off and use the bach pressure created to through a switch turning the pump on and off. the first hurdle is what swithch will work and where can I get it.