diff --git a/pioreactor/automations/led/base.py b/pioreactor/automations/led/base.py
index 17d89662..969b07f4 100644
--- a/pioreactor/automations/led/base.py
+++ b/pioreactor/automations/led/base.py
@@ -264,12 +264,16 @@ def __setattr__(self, name, value) -> None:
             self._latest_settings_ended_at = None
 
     def _set_growth_rate(self, message: pt.MQTTMessage) -> None:
+        if not message.payload:
+            return
         self.previous_growth_rate = self._latest_growth_rate
         payload = decode(message.payload, type=structs.GrowthRate)
         self._latest_growth_rate = payload.growth_rate
         self.latest_growth_rate_at = payload.timestamp
 
     def _set_OD(self, message: pt.MQTTMessage) -> None:
+        if not message.payload:
+            return
         self.previous_normalized_od = self._latest_normalized_od
         payload = decode(message.payload, type=structs.ODFiltered)
         self._latest_normalized_od = payload.od_filtered
diff --git a/pioreactor/automations/temperature/base.py b/pioreactor/automations/temperature/base.py
index a6f59a10..aa232a08 100644
--- a/pioreactor/automations/temperature/base.py
+++ b/pioreactor/automations/temperature/base.py
@@ -116,9 +116,7 @@ def latest_growth_rate(self) -> float:
             # this should really only happen on the initialization.
             self.logger.debug("Waiting for OD and growth rate data to arrive")
             if not all(is_pio_job_running(["od_reading", "growth_rate_calculating"])):
-                raise exc.JobRequiredError(
-                    "`od_reading` and `growth_rate_calculating` should be Ready."
-                )
+                raise exc.JobRequiredError("`od_reading` and `growth_rate_calculating` should be Ready.")
 
         # check most stale time
         if (current_utc_datetime() - self.most_stale_time).seconds > 5 * 60:
@@ -135,9 +133,7 @@ def latest_normalized_od(self) -> float:
             # this should really only happen on the initialization.
             self.logger.debug("Waiting for OD and growth rate data to arrive")
             if not all(is_pio_job_running(["od_reading", "growth_rate_calculating"])):
-                raise exc.JobRequiredError(
-                    "`od_reading` and `growth_rate_calculating` should be running."
-                )
+                raise exc.JobRequiredError("`od_reading` and `growth_rate_calculating` should be running.")
 
         # check most stale time
         if (current_utc_datetime() - self.most_stale_time).seconds > 5 * 60:
@@ -164,6 +160,9 @@ def __setattr__(self, name, value) -> None:
             )
 
     def _set_growth_rate(self, message: pt.MQTTMessage) -> None:
+        if not message.payload:
+            return
+
         self.previous_growth_rate = self._latest_growth_rate
         payload = decode(message.payload, type=structs.GrowthRate)
         self._latest_growth_rate = payload.growth_rate
diff --git a/pioreactor/pubsub.py b/pioreactor/pubsub.py
index 533f0d0e..a3c93b0e 100644
--- a/pioreactor/pubsub.py
+++ b/pioreactor/pubsub.py
@@ -295,14 +295,14 @@ def on_connect(client: Client, userdata: dict, *args):
     return client
 
 
-def prune_retained_messages(topics_to_prune: str = "#"):
+def prune_retained_messages(topics_to_prune: str = "#") -> None:
     topics = []
 
     def on_message(message):
         topics.append(message.topic)
 
-    client = subscribe_and_callback(on_message, topics_to_prune, timeout=1)
-
+    client = subscribe_and_callback(on_message, topics_to_prune)
+    sleep(1)
     for topic in topics.copy():
         publish(topic, None, retain=True)