Originally Posted by kh54s10
No need to remove the blow off tube. Think of it as a giant airlock.
This. If I do switch to an airlock from a blowoff tube, I like to do it while the blow off tube is still bubbling several times a minute. This way you know the postive pressure of the escaping c02 will prevent any chance of oxidation during the switch.
It's probably overly anal, but I just try to reduce the chance for oxidation whenever possible.