Add missing documentation to eheimdigital for quality scale (#39878)

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

source/_integrations/eheimdigital.markdown

@@ -40,6 +40,18 @@ Host:
     type: string
 {% endconfiguration_basic %}
 
+## Data updates
+
+The integration connects locally via WebSocket to the EHEIM Digital main device and requests data updates for all devices every 15 seconds by default.
+
+## How you can use this integration
+
+You can use this integration to control and monitor your EHEIM Digital aquarium devices directly from Home Assistant. This includes adjusting settings such as temperature, light brightness, and filter speed, as well as monitoring the status of your devices.
+
+- **Receive notifications**: Get notified about important events, such as when the filter needs servicing or if there is an error with the device.
+- **More flexible day/night cycles**: Use Home Assistant's automation and scripting capabilities to create more complex day/night cycles for your aquarium devices than the native EHEIM Digital interface allows.
+- **Integrate with other devices**: While EHEIM Digital devices can interact with each other in a limited sense (for example, the EHEIM autofeeder can pause the filter pump after feeding), this integration allows you to automate and control your EHEIM Digital devices in conjunction with other smart home devices.
+
 ## Supported devices and entities
 
 Currently, the following devices and entities are supported:
@@ -106,6 +118,39 @@ Currently, the following devices and entities are supported:
 
 Support for additional EHEIM Digital devices and entities will be added in future updates.
 
+## Automations
+
+### Send a notification when the filter has an error
+
+You can set up an automation to notify you when the filter has an error. This example uses the `notify.notify` service to send a notification:
+
+{% details "Example automation to notify about filter errors" %}
+
+{% raw %}
+
+```yaml
+alias: Notify about filter error
+description: "This automation sends a notification when the filter has an error."
+mode: single
+triggers:
+  - trigger: state
+    entity_id:
+      - sensor.aquarienfilter_error_code
+    to:
+      - rotor_stuck
+      - air_in_filter
+conditions: []
+actions:
+  - action: notify.notify
+    metadata: {}
+    data:
+      title: The filter has a problem!
+```
+
+{% endraw %}
+
+{% enddetails %}
+
 ## Removing the integration
 
 This integration follows standard integration removal, no extra steps are required.