You want to create full, incremental and differential backups. Each full backup should be written to a separate tape in order to send tapes with full backups to a secure off-site storage.
Sequence of actions
Load tapes into the tape device slots.
Perform the fast inventorying with the Move newly detected tapes from the 'Unrecognized tapes' or 'Imported tapes' pools to the 'Free tapes' pool check box selected.
Result. The loaded tapes are in the Free tapes pool. If some of them are sent to the Acronis pool or a custom pool, this means the tapes contain backups you did earlier on this machine. Move such tapes to the Free tapes pool manually if you don't need these backups.
Decide whether you want to back up to the default Acronispool or to create a new pool.
If the chosen pool is not replenishable, move all of the loaded tapes from the Free tapes pool to it.
In Drives, select the entire tape device. This will enable simultaneous backup of the machines via different drives, if your tape device has more than one drive.
In Tape pool, select the pool where you will back up to (the Acronis pool or the newly created one).
Choose the created vault as the backup destination.
Select the Grandfather-Father-Son (GFS) backup scheme.
Specify the rules to keep daily backups for 7 days, weekly ones for 4 weeks and monthly ones indefinitely.
Click Show backup type, 2nd location..., and then select Full/incremental/differential in Backup type.
In the Tape management window of backup options, select For each full backup under Always use a free tape.
After a full backup is created, you can eject the tapes with it and send them to a secure off-site storage. If you do not have enough free tapes to continue backups, load new tapes and perform steps 2 and 4.
Result
The machine will be backed up to tapes according to the specified backup scheme. Tapes with full backups will be sent to a secure off-site storage.