Too-low temp = loss of bacteria??

[Saje]

I've been fishlessly cycling a tank which has finally finished I think. Everything has dropped to 0/0 ... nitrates around 40. I'm gonna assume this thing is now cycled. I had turned the temp up to 80 while it was cycling, but needs to be 75 for adding my diffusa back in. So last night I turned it down a bit (same setting that it had been keeping the water at 75 with) and figured I'd add everyone back in this morning. Welllll, my heater "malfunctioned" and apparantly never came back ON so the temp was right about 70 when I woke up. :mad: (For a timeline as to how long the temp was low: I turned it down from 80 around 1 AM and saw it at 70 around 9 AM. House is 68 from about midnight on.) Obviously, I've now turned it up in an effort to get the water heated up again (it shows it's heating...).

Question is, I know the bacteria don't do well under about 74 or thereabouts .... have I now lost all or most of the colonies that I've just gone crazy building up?? Can I still assume they made it through just fine and it's cycled and healthy and ready to add inhabitants back in or do I need to continue testing and adding an ammonia source and all that?

[J double R]

The bacteria are and will be just fine. :) 70 isn't going to bother them one bit.

If it really bothers you, just be meticulous in parameter testing, as you should be the first few days after adding fish anyway.

Also: if your heater "malfunctioned", get a new one. Don't put fish in that water until you've sourced a reliable heater or figured out what was wrong with that one.

[Saje]

:) Thanks so much - I feel lots better. I had visions of having to start all over again. :shakehead:

Yep! New heater being bought today!

Thanks so much again!

[J double R]

nah, it's all good. ;) a lower temp may slow them down, but it takes a lot to shock those little organisms. Glad you're back on track. :)

[THE V]

The bacteria would survive even if the water in the tank had frozen. They do live in permafrost in the arctic and survive the winters in the cold regions.

They just stop metabolizing nitrogen below 41F but they survive just fine.

[Saje]

Ahh! Good to know for sure. I remember reading, when I had a coldwater tank, that the bacteria didn't do so well under something like 73ish. Awfully glad to hear that's not exactly right.

Thanks guys. :)