I like using a blowoff in a Mason Jar. Not only does it sound cool when it starts continuously bubbling. But as an added bonus you can make Hop flavored Seltzer Water for free :-D (just use fresh water without StarSan or anything)
You can safely change to a blow off tube. When fermentation is that active you have very little chance of infection. I woke up one day with beer in my airlock. I thought I would be able to just clean the airlock and move on....pulled the airlock off and it started coming out the top. Moved over to a blow off tube and within 30 seconds I had foam halfway through the tube.
What I woke up to:
Here is what it looked like about 30 seconds after getting the blow off tube on:
That's why I don't want to pull it yet. It will most likely juts start shooting out all over the place. Cant't see in the picture obviously, but the fermentation in the glass is crazy! Fingers crossed... A few more hours and I will attempt to pull it.
Didnt take readings on ANY of those 3 hahah I dont really care. Not doing secondary. The double IPA will go 4 weeks, the other two will be done in 3. I just wanted to get back in to brewing. Next time I will be more meticulous and include alcohol content.
Lesson learned though. No more cheap airlocks. Especially on a 5 gallon carboy!