I did not use an air lock.
I used a separate blow-off container but the lower temp cause a pressure change which forced it up the tube and into the carboy.
The sanitizing solution I am talking about IS A NO RINSE SANITIZER recommended on one of the home brew podcasts. The 1/4 cup vinegar / bleach to 5g solution was recommended by the maker of Starsan...
I use this on all of my equipment, including bottles, caps, etc.
Also, after 4+ weeks in an open bottle all the chlorine would have been gone....