Dry airlock, funny thing happening

Ok, I made 10 gal of a nice pale ale. I put 5 gal in a 6 gal carboy and the other 5 gal in a 5 gal carboy. Pitched a pack of notty in each and in 6 hours they both started bubbling away, no problem.
The next morning I saw that on the 5 gal carboy the krausin pushed through the airlock and it was dry, I filled it. Now 4 days later the 6 gal carboy if finished but the one that went dry is bubbling away, lots. I don't think it's yeast activity, It looks like tiny co2 bubbles rising to the top. Is it ruined? What happened?
Help me understand what it could be.

 

Unless there's something more beyond what you're describing. I would say it is fermenting.

 

Why is the batch next to it done 2 days ago?
Same batch, Same yeast?

 

Who knows why yeast do what they do. Can you take a hydrometer sample to see where the gravity is at? That will give you a better idea.

 

Very true! I'll go check the gravity now.

 

Had the same dry airlock scenario happen to me...Beer turned out just fine...im drinking some now actually

 

Yes hydrometer will tell you. Any change in temperature?