chetan99
Disciple
I actually do remember about this concern and you are right. It can be a problem in some pump designs (don't remember which ones). I'm assuming the ones in these vacuums would be able to deal with it because it's designed to run when there is no water left in the tank as well, but no way to be certain I guess. I have been putting the drop of liquid soap every now and then and things are working normally is all I can say.