Backup exec 2014, Backup size 1.2TB, HP tape LTO6, media is not enough, overwrite is configured

Hi,

We have backup exec sp1 installed on server 2012R2,

The backup is written to HP Tape LTO6 - 2.5TB Native, 6.5 Compressed.

Daily backup size is 1.2TB

In most of the week day the backup job is ejecting the cassette from the tape and ask for new cassette.

I have for each day of the week a different cassette and i don't understand why the cassette is not enough.

The job storage settings is configured to overwrite media and keep data for 1 hour, compression is configured for hardware if available otherwise software.

Backup exec settings:

 I need that the backup will fit on 1 cassette.

Kind Regards,

Eliran