PET Fermenter and blow off

I’m new to brewing… I bought a 5 gallon plastic PET Fermenter. I can’t see what is going on in the bucket… how would I know if and when I need to use a blow off tube? Other than seeing wort traveling through the airlock and possibly the lid bowing…

Install a blow off tube assembly at the start of each new fermentation. You may not see krausen rising in the air lock in time to save the lid and surrounding area from major clean up.

Five gallons of beer in a five gallon bucket? If this is the case the lack of headspace will require a blow off tube all of the time. Five gallons of beer in a 6.5 gallon bucket would be best.

Overactive fermentations are often the result of the fermentation temperature being to high. Have a method in place to control the wort temperature.

I forgot to add this. The height of the krausen can be seen by opening the bucket for a peek, removing the airlock and looking in, or shining a light through the bucket, from the opposite side. Try the light method first. No risk of contamination.

Always sanitize the top of the fermentor when it will be opened.

6.5 gal. sorry… Im going to be leaving the fermentor in my house unattended… So far it’s been okay thanks for the advise