As the documentation says QueueCountAlert is only to monitor queue for the configured number of threshold limit. It is not designed for monitoring the queue that either only keeps growing or stopped processing messages (though the queue count may also be an indication of this).

QueueWaitAlert can be used to alert if the messages are not processed or slower than usual. But this doesn't monitor for growing queues primarily. This checks for the first message in the queue on how long it is in the queue and alerts if the queue waiting time is more than the configured threshold on QueueWaitAlert. 

Managed Alerts can be also used which is a work flow based alert management.

Alternative is to create a custom service (refer OnProcessInput method in Ens.MonitorService.cls) to implement the required Monitoring to the production.