Where do these elusive bacteria live anyway?

Well if it helps. Last year I moved twice. The second time I moved my 55g I put my fish, plants, and filter media in separite plastic tubs. For reasons I won't go into on this thread I had to change my substrate. The move itself took about 2 hours total plus maybe an hour to get the aquarium back up and running. This was with new substrate and a 100% water change. Once everything was back together I tested the aquarium after 2 hours, then 4 hours, then the next day, and so on. In that time I never had detectable amounts of ammonia or nitrite using API tests. I can't say exactly how much bacteria I might have lost. I can say that my single filter did what I was hoping it would, that is pull thru without a hitch. I don't run 2 filters on this aquarium, but I do have a back up filter capable of holding all of the bio media in my current filter along with at least half of the sponge media. Of course if I'm gone for a week and something bad happens to the filter I'll most likely be sunk.
 
Thanks hound - that was precisely the kind of information I find useful. What style of filter was it? HOB, canister, wet/dry?
 
Those with Expertise - please correct/comment

So summary of :read: research - feedback indicates:
(all errors and misconceptions are likely due to my own nooB-ness - not due to someone else's misdirection!)

1. The bacteria probably live everywhere they can get oxygen, water and food, and a surface to attach to

2. in gravel, unless using UGF, they are likely only on the surface, since below that there is not enough circulation to provide the necessary nutrients.

3. In filters - they are living in the medium such as filter floss, sponges, bio-wheels, etc.

4. they seem to adhere fairly well, so simple tasks such as vacuuming gravel is not going to suck them off the gravel.

5. They are fairly sensitive to chlorine (tap water levels) and pH (big changes can inhibit function or terminate them)

Some conclusions I drew are:
The "Nitrite to Nitrate" oxidising bacteria probably double in 1/2 a day - thus removing/losing one of two HOB type filters is not the end of the world, since that probably only costs less than half the bacteria, and that deficit can be made up in less than 1/2 a day.

However, losing the only canister / sump type wet/dry would be a disaster since the gravel and tank hardscape surfaces would not house sufficient bacteria to keep the tank from cycling. I have not figured out how to create a safety backup if using canister/sump type filtration.
 
placing sponges on the in and outflows of the canister (in tank) will allow bacterial colonies to grow there, just have to squeeze them out once or twice a week in old tank water to remove any physical waste buildup. also if you use a powerhead with a sponge the same thing will happen. not quite a backup system, but it does spread the bacteria around even more instead of concentrating it in the canister itself.

The "Nitrite to Nitrate" oxidising bacteria probably double in 1/2 a day - thus removing/losing one of two HOB type filters is not the end of the world, since that probably only costs less than half the bacteria, and that deficit can be made up in less than 1/2 a day.

Someone please feel free to correct me if i am wrong, but I'm pretty sure it takes the same amount of time for one bacterial cell to split into two as it does for 1 million to split into 2 million. so whenever you try to double the population, it still takes the full amount of time.
 
Someone please feel free to correct me if i am wrong, but I'm pretty sure it takes the same amount of time for one bacterial cell to split into two as it does for 1 million to split into 2 million. so whenever you try to double the population, it still takes the full amount of time.

You are right - doubling the population takes, on average, the mean time for a doubling (given mean conditions, availability of resource etc.)

However, I proposed that you lose less than 1/2 the colonies since some bacteria continue to live on the hardscape and gravel, so they need less than 1/2 the doubling time (1/2 day) since they don't quite need to double.

As an illustration, if 1/3 die off, leaving 2/3, then they only need to grow by 50% (or 1/3 of original amount) ;), which would take 7 hours at a 12 hour double rate. (yes - its not 6 hours - its ~7 - geometric series math)
Its not like they double in one binary step - they grow continuously till resources are used up.....
 
However, losing the only canister / sump type wet/dry would be a disaster since the gravel and tank hardscape surfaces would not house sufficient bacteria to keep the tank from cycling. I have not figured out how to create a safety backup if using canister/sump type filtration.

If the tank is well established (say 6 months or more) I'm not sure I would necessarily agree with this statement, if a new filtration system could be immediately provided. I think that there would be enough existing bacteria on every surface area of the tank to stave off a cycle, unless perhaps the tank had no substrate. The growth of beneficial bacteria is obviously self-limiting once equilibrium is met, namely the stable supply of ammonia to feed upon and convert to keep bacteria reproducing. However, I also believe that bacterial growth would accelerate once that equilibrium was broken. An addition of a product like Seachem Stability would help increase the amount of beneficial bacteria during such an event. However, particularly for large tanks and those with large bioloads, the benefit of having two, independent filters operating can not be over stressed.
 
or even if you don't keep it on the tank, having an extra HOB filter around could be good - if you are back home within a few hours of the canister breaking down everything should still be okay, and you could take the biomedia (i'm not exactly sure what is inside of canisters) and put it into the back of the HOB filter, and use that as emergency filtration/aeration until you get the canister working again. not ideal, but better than nothing.
 
If the tank is well established (say 6 months or more) I'm not sure I would necessarily agree with this statement, if a new filtration system could be immediately provided. I think that there would be enough existing bacteria on every surface area of the tank to stave off a cycle, unless perhaps the tank had no substrate.

That makes a ton of sense, if and only if, there is sufficient bacteria in what remains. If the tanks supports 16 million li'l critters ;), will they likely be 15 million in the canister, and 1 on the substrate etc.? If so, it will take them 4 x doubling time to regain former strength with a new filter. (naturally, other distributions yield other results. Lacking hard core scientific observation, I was trying to come up with an understanding from empirical observations, rather than conjecture. 'Cause it has been said 'Life will find a way'

The growth of beneficial bacteria is obviously self-limiting once equilibrium is met... However, I also believe that bacterial growth would accelerate once that equilibrium was broken.
Why would you believe that? They can't behave differently than their nature, can they?
I can see two ways that they can behave as if they are growing gangbusters -

1. If the excess bacteria go into hiberrnation when they don't get enough food. Then, they could spring into action when competition decreases, without having to go through a full reproduction cycle.

2. If the extant bacteria hang out, loafing at less than full capacity. Then they could shift into high gear when more resources were suddenly available - and continue with the usual reproduction too...

In any case, empirical observation would confirm that 'rapid recovery'. I am guessing that there is something going on since people seem to have equipment/sickness issues, and recovery is less onerous than the initial cycle set-up.

Again, my goal is just to set my tanks up with a robust framework without putting all my 'fishies in one filter' - and I am just collecting information form other people's experiences.
 
i think this is a really good thread, maybe with some editing and clarity it could be made into a sticky or rewritten as an article..
 
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