@longpvo - I might use a Single Pole Single Throw (SPST) relay with contacts rated for the maximum amps that the pump would pull in combination with a power supply that will supply the needed amperage. Use the Rachio M terminal to close the relay by connecting it to the relay coil with the other side of the relay coil connected to the Rachio C terminal. Connect one side of the power supply to the pole on the relay with the other side of the relay going to the pump and the other side of the power supply going to the pump. If one wanted to switch both leads coming from the power supply then the relay could be changed to a Double Pole Single Throw (DPST) or a Double Pole Double Throw (DPDT) relay which may be easier to find - just don’t connect up the normally closed contacts on the DPDT relay to anything.
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