With this schedule, you need at least 9 tapes if you want to reuse daily tapes, which is not recommended. Preferably, you need 21 tapes if you save weekly tapes for a month: one tape for the level 0, 4 tapes for the Fridays, and 4 or 16 daily tapes.
1 tape for the level 0 backup
4 tapes for all the Friday backups
4 or 16 daily tapes
If you need to restore the complete file system, you need the following tapes:
The level 0 tape
The most recent Friday tape
All the daily tapes since the last Friday tape, if any