wyeast 2112 - No Krausen

I brewed a New Belgium 1554 clone last weekend and used the wyeast 2112 to ferment it (i know a european lager yeast would have been better but i didn't have any readily available) in any case I pitched at around 78 degrees, and fermentation seemed to start off pretty good. I then started to lower the temp a bit by adding ice packs to the water that the fermenter was sitting in. Temps lowered to around 70-74 sometimes sneaking back up to 76degrees on a hot day. Fermentation seems to be continuing, but it hasn't formed any krausen or even a layer of bubbles over the top since i started the temp lowering. Do I have much to worry about? could it have sucked back some sanitizer from the airlock and killed the majority of the yeast? I'm going to take a gravity reading this weekend to see where I'm at. should i pitch more yeast?

It's (most likely) done. You fermented it WAY too hot.

the recipe i was going off of mentioned fermenting it at ale temps to get the estery banana flavors? then cold crash it... i guess it was still to high? oh rats.