Make sure you're on Hidden Mansion, the vacuum is 1.5x faster than the normal mansion. As a generality, you're going to want to pull the .
In the regular mansion it's hard to capture portrait ghosts and blue/green ghosts in one attempt, but in the hidden mansion it is ALOT faster, .
For Luigi's Mansion on the GameCube, a GameFAQs message board. HP faster, but allows the ghost to more easily break the connection.