Fishless Cycling Question

[rebrn]

Ok this is probably a stupid question, but I can't find the answer anywhere. Here goes...When your tank has completely cycled (meaning you have gone at least a week with ammonia/nitrites dropping to 0ppm within 12 hours) and you do your water change, how long do you have, with out adding ammonia, before the bacteria die? The reason I ask this is while fishless cycling I have my tanks running at about 85 F (confirmed with continous temperature readings), and I know that after the large water change at the end that the water temp should come down quite a bit, however the water temp may come down too much (I am thinking in particular of my Betta Tank) and I may have to let it heat up again. Essentially, my plan was to do the large water change at the end of the cycle, confirm water stats are good, then go to the LFS to buy fish. In the 45 minutes or so it would take me to go to drive to the LFS, pick my fish, and drive home, I am certain that temp would be come up (or go down) enough for my fish, but is that too long to go without an ammonia source? I am thinking it would probably be closer to 1.5 - 2 hours total before the fish were actually added, taking into account acclimation time.

I know stupid question, but I have worked so hard to get these tanks ready (still not there yet) I just don't want to mess it up at the end

Thanks

 

[MrPurplePickle]

It won't be a problem.
It doesn't die off that quickly.

When my tank finished cycling, 90% water change on the Friday night, bought fishies arounf midday Saturday.

 

[rebrn]

It won't be a problem.
It doesn't die off that quickly.

When my tank finished cycling, 90% water change on the Friday night, bought fishies arounf midday Saturday.

I figured it would take longer than a few hours, but just wanted to be sure. After all this work I didn't want to mess it up right at the end.

Thanks again.

 

[JustFrozen]

someone here (sorry i forget who) said recently that the old saying "it's better to be safe than sorry" especially applies to this hobby. i believe that to be true and you shouldn't feel awkward or sorry about asking even a simple question, especially here where everyone is super helpful and courteous

 

[rgrrmg]

Excellent question as I am close to the end of my fishless cycle, and wondered the same thing myself.

The only stupid question is the one not asked...

 

[rebrn]

Glad to hear I wasn't the only one questioning this. Thanks

 

[waterdrop]

Agree with the Pickle, You've got pretty much time and shouldn't worry.

Here's the way I think about "die-off" topics with respect to our beneficial bacterial colonies:
(and perhaps those more experienced than me might have enhancements to these of course)

The bacteria die off very slowly the first day or two, then faster and faster. If you plotted it on a graph the line of die-off over time would be a curve starting off going up slightly and then turning a corner and going up steeply.

The major categories one tends to think about in conjuction with this topic are:
1) No Ammonia Source - slowest die-off curve (this is the one discussed in this thread)
2) No Ammonia plus No steady water movement across media - this is a little worse as there's less oxygen
3) No Ammonia plus media drying out - this is the worst - rapid death.

~~waterdrop~~