My experience is the same as Barnsnake. A recovery tank or bottle with the fitting on the bottom hooked up to your surge tank will eventually get the bubble out. Mine gurgled after shutdown for about two weeks (weekend only driving). Then it caught the bubble and now all is quiet. Just keep topping it off until you can't add any more. Make sure there is some distilled water first in the recovery tank so it makes a good siphon back to the surge tank.
