SafeHouse volumes can be optimized (defragmented) just like any other Windows drive. Neither Windows nor SafeHouse knows the difference.
Open your volume.
Launch the drive optimizing utility and point to the SafeHouse drive letter.
If for some reason the SafeHouse drive letter is not listed by your drive optimization software, or the software reports that it is unable to work with the SafeHouse drive letter, then try restarting Windows and re-opening the SafeHouse volume. Sometimes Windows gets confused as SafeHouse volumes are opened and closed and then re-opened. When this is the case, the easy cure is simply to run the optimizer the first time the volume is opened after restarting.