I do use airlocks (I don't rely on them though) for 2 out of my 3 fermenters. Is there a good reason why I shouldn't (eg nasty backwash)? I get small bugs in my airlock occassionally but my assumption has always been they can only go halfway. If I'm wrong I'd like to change (although no flies or whole brew infections yet).
Good question- one I've wondered about quite a lot. I decided to bypass it altogether, by first going to two- piece airlocks (removing the top piece at sampling) and then just to film.
Now, I can't be sure there's not something in the airlock I can't afford to be sucked back into the brew either at sampling or when I pick it up. Chances are, there's really nothing to worry about, but every sampling time when I did get a teensy bit of backwash go all the way back into the brew, I thought there had to be a better way. Hence I said, stuff this, I'll eliminate the possibility by using film. There is _usually_ some pressure behind the film, so bugs are excluded unless they can swim through constant gas expiration (mostly CO2 I presume).
Some folks use sanitiser in their airlock _just in case_ some of the fluid in the airlock has come to be containing nasties. (Its probably pointless using meta for this BTW, I suspect it has to be chlorine- based or an iodophor for that to work.)
It gets a bit anally- retentive, for sure, but its one less thing I have to worry about.
I also have a totally different, but none the less quite valid reason- one of my fermenting fridges, usually reserved for secondaries, has just enough room for two fermenters on separate shelves with just film, whereas it would only fit one with an airlock. So, height restrictions came into play. I usually have three brews underway most of the time, whether in cubes or fermenters, so if I can fit two together in one fridge, for sure- I will. I only have two fridges for fermenting...
