I take it when you mention the media pool, you are backing up to disk, then backing up that back-up-to-disk folder to tape.
Your protection periods are almost certain to give you problems. Please tell me what you are trying to accomplish, and what your job settings are so I can make some suggestions. For example, I have 20 tapes and I do a daily on the first four, a weekly on the next four, and a monthly on the last 12. My job is set to overwrite the tape and I only put one job on each tape, or I append jobs, etc.
In general, if I am just doing one job to one tape, I set the overwrite protection period to 0 hours (turns it off) so I can overwrite the tape at will. You should also look at Tools>Options>Media Mangement, and set it as you desire. I personally set that to none and uncheck the "Prompt" box. In my job I then set it to simply overwrite the tape. In the above one-tape scenario, I set the append time to infinite.
If you save tapes and it is important that they not be overwritten, put them in a separate media pool with the longer overwrite period you desire, which may require making them a separate job too.
Append can be trickier because there are two situations. First is I have a job that appends my daily bacckups for Monday-Wednesday, but I ONLY want this week's at any given time, so I set the append period to 6 days. After 6 days, it overwrites.
The second situation deals with space and not wanting to have to pop a new tape when you come in. If you have a large tape like 800GB that can hold 4 of your 175GB backups, which you do weekly, that means in the 5th week you would come in and the job would be asking for another tape. To avoid that, you set the append period to either 4 weeks or 30 days, for example. That way on that 5th week, it will not append, but overwrite it and start again.
