Can you check you have alert enabled in your telemetry configuration? Remember you have to reload reef-pi if you change telemetry configuration, for it to take effect.It is not calling to send message.
Jan 30 20:26:41 raspberrypi reef-pi[25088]: 2019/01/30 20:26:41 ato sub-system: sensor ATO value: 1
Jan 30 20:26:41 raspberrypi reef-pi[25088]: 2019/01/30 20:26:41 Setting GPIO Pin: 5 State: 0
Jan 30 20:26:46 raspberrypi reef-pi[25088]: 2019/01/30 20:26:46 ato sub-system: sensor ATO value: 0
Jan 30 20:26:46 raspberrypi reef-pi[25088]: 2019/01/30 20:26:46 Setting GPIO Pin: 5 State: 1
Jan 30 20:26:51 raspberrypi reef-pi[25088]: 2019/01/30 20:26:51 ato sub-system: sensor ATO value: 0
Jan 30 20:26:51 raspberrypi reef-pi[25088]: 2019/01/30 20:26:51 Setting GPIO Pin: 5 State: 1
Jan 30 20:26:56 raspberrypi reef-pi[25088]: 2019/01/30 20:26:56 ato sub-system: sensor ATO value: 0
Jan 30 20:26:56 raspberrypi reef-pi[25088]: 2019/01/30 20:26:56 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:01 raspberrypi reef-pi[25088]: 2019/01/30 20:27:01 ato sub-system: sensor ATO value: 0
Jan 30 20:27:01 raspberrypi reef-pi[25088]: 2019/01/30 20:27:01 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:06 raspberrypi reef-pi[25088]: 2019/01/30 20:27:06 ato sub-system: sensor ATO value: 0
Jan 30 20:27:06 raspberrypi reef-pi[25088]: 2019/01/30 20:27:06 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:11 raspberrypi reef-pi[25088]: 2019/01/30 20:27:11 ato sub-system: sensor ATO value: 0
Jan 30 20:27:11 raspberrypi reef-pi[25088]: 2019/01/30 20:27:11 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:16 raspberrypi reef-pi[25088]: 2019/01/30 20:27:16 ato sub-system: sensor ATO value: 0
Jan 30 20:27:16 raspberrypi reef-pi[25088]: 2019/01/30 20:27:16 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:21 raspberrypi reef-pi[25088]: 2019/01/30 20:27:21 ato sub-system: sensor ATO value: 0
Jan 30 20:27:21 raspberrypi reef-pi[25088]: 2019/01/30 20:27:21 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:26 raspberrypi reef-pi[25088]: 2019/01/30 20:27:26 ato sub-system: sensor ATO value: 0
Jan 30 20:27:26 raspberrypi reef-pi[25088]: 2019/01/30 20:27:26 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:31 raspberrypi reef-pi[25088]: 2019/01/30 20:27:31 ato sub-system: sensor ATO value: 0
Jan 30 20:27:31 raspberrypi reef-pi[25088]: 2019/01/30 20:27:31 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:36 raspberrypi reef-pi[25088]: 2019/01/30 20:27:36 ato sub-system: sensor ATO value: 0
Jan 30 20:27:36 raspberrypi reef-pi[25088]: 2019/01/30 20:27:36 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:39 raspberrypi reef-pi[25088]: 2019/01/30 20:27:39 Reading temperature from device: 28-01131e872049
Jan 30 20:27:39 raspberrypi reef-pi[25088]: 2019/01/30 20:27:39 Reading temperature from device: 28-0213169a87aa
Jan 30 20:27:39 raspberrypi reef-pi[25088]: 2019/01/30 20:27:39 health check: Used memory: 14.45 Load5: 0.02
Jan 30 20:27:40 raspberrypi reef-pi[25088]: 2019/01/30 20:27:40 temperature sub-system: sensor Sump-Temp value: 77.45
Jan 30 20:27:40 raspberrypi reef-pi[25088]: 2019/01/30 20:27:40 temperature sub-system: sensor Tank-Temp value: 77.5616
Jan 30 20:27:40 raspberrypi reef-pi[25088]: 2019/01/30 20:27:40 temperature subsystem: Current temperature is within range switching off heater/cooler
Jan 30 20:27:40 raspberrypi reef-pi[25088]: 2019/01/30 20:27:40 Setting GPIO Pin: 6 State: 0
Jan 30 20:27:41 raspberrypi reef-pi[25088]: 2019/01/30 20:27:41 ato sub-system: sensor ATO value: 0
Jan 30 20:27:41 raspberrypi reef-pi[25088]: 2019/01/30 20:27:41 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:46 raspberrypi reef-pi[25088]: 2019/01/30 20:27:46 ato sub-system: sensor ATO value: 0
Jan 30 20:27:46 raspberrypi reef-pi[25088]: 2019/01/30 20:27:46 Setting GPIO Pin: 5 State: 1
Jan 30 20:27:51 raspberrypi reef-pi[25088]: 2019/01/30 20:27:51 ato sub-system: sensor ATO value: 0
Jan 30 20:27:51 raspberrypi reef-pi[25088]: 2019/01/30 20:27:51 Setting GPIO Pin: 5 State: 1