rgaskell,

As long as your end users are NOT making any complaint, you are ok.
The "TEMP Tablespace" blow out problem is on the every oracle instance. Even if you add another 20 GB space, you will still find it again becuase of the SQL statement executed by the application that does cartesian product of 2 big tables.

You need to talk to the developers/end users to correct the SQL statement.

Tamil