:icon_offtopic:
Ref: Cling wrap.
Does the build up of CO2 pop it off the top?
Do you ever release any pressure from the fermenter?
I spose, drawing a sample every couple of days might equalise the pressure inside the fermenter?
In a vigorous ferment the cling wrap "domes" up but has never popped off or been close to it. No need to release pressure, in fact, the tightness of the cling wrap is an indication of where your brew is at. I use it as an indicator of when I should start to take SG readings.
Think of the clingwrap as an iphone compared to the 2002 Nokia of "lid and airlock".
Simple to use and intuitive.
Cheers