DiskSpaceMonitor running hourly not as specified in crontab

hi, i set up diskspacemonitor according to the instructions in an article on this website. i set the frequency for the diskspacemonitor check to run in the roots crontab to be 1440 minutes. however it is checking hourly. i changed the time to 720 minutes but it is still running hourly. no crontab exists for the admin login account. any ideas how i can fix would be welcome. $ cat system.log Feb 18 03:15:01 macserver2 syslogd: restart Feb 18 04:00:00 macserver2 CRON[5390]: (root) CMD (/usr/sbin/diskspacemonitor check) $ sudo crontab -l */720 * * * * /usr/sbin/diskspacemonitor check $ cat diskspacemonitor.conf # Config for diskspacemonitor # monitor_interval=720 # Check disks at this interval, in minutes alert_threshold=85 # When a disk is this percentage full, execute # the alert scripts in # /etc/diskspacemonitor/action/ recovery_threshold=95 # When a disk is this percentage full, execute # the recovery scripts in # /etc/diskspacemonitor/action/ log_file=/var/log/diskspacemonitor.log