i thought of using both because once i had foam get into the airlock and clog it, causing the lid to blow off my 5 gallon bucket, and causing a huge mess.
With the that orange top piece people often have for carboys, there are 2 exits on it. I figured if i put the airlock hose on one exit and the air lock on the other, it would (hopefully) leave one exit freed if the foam gets too high and clogs the other. Just figured the more exits for CO2 incase of foam causing clogging, the better. I know its likely overkill.
:rockin::rockin::rockin: