I'm in the primary fermentation of mead, using one of these "big mouth bubbler" 5 gallon fermenters and an S airlock.
Initially, when the fermentation was really vigorous, the airlock behaved as expected, bubbles pushed through every second or so, and then slowed down. Recently, however, the level in the airlock is almost even - it's still slightly lower on the fermenter side, suggesting that there's pressure being held inside, but not much, and it's not going down. This despite the fact that bubbles are still clearly rising inside the liquid in the fermenter.
At one point, I took apart the lid, stopper and airlock, cleaned everything and re-attached it (thinking there might be some gunk preventing a seal), and this seemed to solve the problem for about a day (airlock immediately pressurized, and started bubbling every couple of seconds), but the next day, the problem returned.
Is there any explanation other than a potential leak somewhere? The fermenter is brand new.