AKKR8 has a relay output, the output can be set to trigger when a specific level of an input has been reached, ie start a pump at a specific value of the analogue input. It can also be used to receive an MQTT-callback, ie trigger it via MQTT.
The relay output is can only drive small loads of up to 100 mA @ 5 V so normally there is a need for an external relay. It is recommended that a fuse is present in this loop, and should be a 50mA to 100mA quick-blow fuse as required by the relay coil resistance.