I've never rearched what temp range beneficial bacteria can survive in, but I can just tell you anecdotally that mine seem to have survived just fine. I reset my tank and, although I had a very brief mild ammonia spike, things settled down quickly and are just fine. The water conditions are good enough that my T. Meeki that I've had only a few weeks paired up and spawned already. So while I can't give you a definite yes or no, I can tell you that my bacteria survived just fine. But I can also say this: Just like any life form, bacteria need to eat. So if you have completely cleaned out your tank and removed anything that can generate ammonia, your bacteria will either die off or at least go dormant on you. Since my fish basically slow cooked for about a week, they mostly disintigrated. I took most of the big remains out of the tank, but purposely refrained from doing a deep clean until I was almost ready to restock so that my bacteria would continue to live.