Using RMAN with DISK and SBT (tape) Devices

I know there are many ways to use RMAN and each of those ways has many options to it.  My intent is to put rman backups to disk in the early morning hours and then use rman to put those disk backups to tape in the evening.  That's what I thought I was doing but I'm not so sure.
I'm using this command for the morning disk backups:
      backup incremental level $LEVEL cumulative database plus archivelog delete input;
where $LEVEL is 0 for full or 1 for incremental.

I've been using this command to put the morning disk backups to tape:
      backup device type sbt backupset all;