I apologize for not responding more quickly. My husband just had rotator cuff repair surgery and he needed assistance; then I forgot to come back to you.
The Hydrotek 1000 is only a pump start relay. The controller was a Rainbird ESP-M. Here is a link to its manual, but I didn’t see anything in it that would help. Rain Bird ESP-Modular User Manual
There is also CentriPro Model CB10412 control box that is attached to the Hydrotek. Here is the manual link. 548671_1_Goulds+Quick+Disconnect+Control+Box+Brochure.pdf
But I used the M and C wires from the Rainbird to wire the Rachio (and then the SPST) and those came out of the Hydrotek so I don’t think the CentriPro matters?
I have sketched a schematic. I am no artist, and it’s not to scale but hopefully it helps. I will upload it from my phone.
Cindy