Rien:
If you are happy with your alert and just want it to fire more than once a day there is a quick simple partial solution we use to handle that situation.
Most alerts only fire once in the desginated window which sounds like an entire day in your case.
To reset the alert before that time is concluded schedule in cron to touch the $HCISITEDIR/Alerts/default.alrt file and that will reset your alerts for that site.
We touch all our defalut alert files in all our sites hourly during the day from 7AM-7PM, which has been a good balance for us.
Thanks Russ, I will study this in more detail.
Bye for now,
Bert (colleague of Rien)