Originally Posted by adamjackson
I've been throwing in about 10MLs of StarSan in my gallon stove pot half full of water and make sure the blow off hose submerges completely in it curling around at least once to ensure any blow-back that ocurrs will just be starsan. It's not a log but that water is sanitized even after it becomes brown.
I wouldn't assume that it's still sanitized, I've had gunk growing in it when I've had particularly large blow-offs. I think I've even had fermentation going on. I only use about a pint of sanitizer solution, though, so a bigger fraction of the jug is wort.
And to the OP, you are safe to go ahead with the airlock. Unless you add a large volume of fresh fermentables, you're extremely unlikely to see a second active fermentation take off.