Is there a way to have the pump relay turn on only for specific zones

[Jer]

I didn’t see this thread but posted the exact same request using rid o’ rust for certain zones in a now 6 year old thread:

Master Valve only on specific zones

So here we are almost 6 years since the first post in this thread and still no option for the master pump on for specific zones. Let me ask for some help from this crew as it looks like I am going to have to go the relay switch route this year. I need help understanding how to wire what I am looking to do so let me summarize. I have an injector pump that injects rid o’ rust into the sprinkler system. Currently this works on the Rachio by setting the injector pump to turn on via the master pump…