I have always used either a blowoff tube or a three-piece airlock (one with the small, floating cap on the exhaust tube) for fermentation. Today's batch is my first using the two-piece (S-shaped) airlock. I filled both chambers to the max line marked on each tube and noticed that, after several hours, the sanitizer from one of the chambers has almost completely transferred to the other side, with only a small amount of sanitizer remaining in the U-bend beneath the two chambers. Is this normal for two-piece airlocks? Should I pull it out and refill again with sanitizer or vodka so both sides are equal in volume?