[Answered ]-Celerybeat – Periodic tasks with Django

Celerybeat is a daemon, it should run in the background permanently (with something like supervisord). Given the fact that your shortest reminder delay is an hour, it should run a task hourly.

This task should check all the campaigns, and decide according to the data from the data base which reminders it should send. To make things easier, I suggest that you calculate and save the next time a reminder should be sent when you send it. This way the next time, listing the reminders to be send will be as easy as listing all overdue reminders.