krausen and no krausen

So I made a ten gallon batch of Belgian Strong ale and split into two fermenters. However I pitched the yeast prior to racking to primary. Both fermenters exploded with activity within 4 hrs and continued for about 3 days or so and both have completely stopped bubbling through the blow off. The only difference is that one still has a thick krausen on top and the other has NOTHING! I have yet to take a gravity reading from either bit am wondering why the difference if they are both the exact same beer and yeast amounts in different containers?

 

exact same kind of fermenters or different? if different, aeration will be different

 

the krausen on one dropped before the other, not that unusual.

 

Same fermenters. I only ask because it's so soon it seems like. I'll take a reading tomorrow and see what's up.