Questions on beneficial bacteria

[MattW]

Sorry if these questions seem a tad newbie. My experience on the micro side of this hobby is pretty minimal.

How long can beneficial bacteria live without an active food source?
Will it survive 24 hours in stagnant water?
Will old & mature substrate be "choked" if used as a bottom layer and covered by fresh substrate? (mature substrate originally coming from the top layer of an old setup)
Is mixing/adding two different mature substrates/filters and their BB colonies into one tank a good idea?

 

[WhistlingBadger]

Well, I'm a music teacher, but I've read Walstad's "Ecology and the Planted Aquarium" three times, and I've spent a lot of time wading through natural substrates (while fly fishing). So that makes me pretty much an expert.

For what it's worth, my answers to your questions would be:
1. At least 48 hours. I've never tried longer than that.
2. Probably. But I'd throw in an airstone for good measure.
3. Probably, but still better than nothing. The ideal would probably be to mix the two together so the old stuff can seed the new. Are we talking sand or gravel? Gravel probably gets enough water circulation to allow the good bacteria to survive and populate the new substrate. With sand, it might just get smothered. But I'm pretty sure it's still worth putting some old stuff in there.
4. Probably, as long as it's free of pathogens and other nasty critters. Biodiversity is our friend.

Hope that's helpful.

 

[jaylach]

First, unless using under gravel filtration, putting old substrate with bacteria below new substrate will likely kill the bacteria due to lack of oxygen. Granted that the bacteria will 'migrate' to the new substrate but I would imaging that the population would be greatly reduced.

In a tank that does not use under gravel filtration the bacteria can last for a while but not forever. In this case it is best to use filter media to transport the bacteria to a new tank. Still, ammonia is needed if there are no fish in the long run. This is solved simply by adding pure ammonia to the tank.

If neither of the above is the case that still does not mean the bacteria will die. From several articles I've viewed, instead of being killed the bacteria will go into a dormant stage. Consider Dr. Tim's One And Only bottles of bacteria. There is about a year of shelf life yet there is no ammonia. This tends to help verify the bacteria going dormant instead of being killed.

 

[AJ356]

I am sure there is some science behind beneficial bacteria going dormant such as the Dr Tim's example, but.... My test results (ammonia and nitrite) on multiple occasions show that if a mature filter media is kept wet in the filter, and the filter is turned off or on and there is no new food source (no fish or new ammonia), after about a week, that filter media will be the same as brand new media. It will need to cycle again from scratch. That's my experience. Either that, or the beneficial bacteria for me, go "dormant" and stay dormant. They down tools and never come back to work!

 

[AJ356]

If I can part hijack the thread Matt, there was another question I was going to post at some point.

Do we think there comes a point when beneficial bacteria simply run out of space on filter media surface? I'm assuming so, (maybe the same principle as media becoming "clogged")...... otherwise we could have a "mega mature" filter sponge that is say... 5 inches x2 inches x2 inches big (like an internal filter size), that would always be sufficient for a 2 foot tank no matter the bio load? (as long as the bio load is increased slowly).

I ask this because I have an example. In a 2 foot fry tank I have, the filter media I have cannot be much more mature than it is. It's been managing a high bio load for well over a year, maybe two years. I'm not talking about it being full of sludge, i give it a very gentle squeeze about once a fortnight. The integrity of the sponge seems fine to me, it still has that "spring" in it's step.

However, I have learned that this filter can only take a certain amount of bio load before I will get a detectable nitrite reading (never ammonia).

Do you think that by now, there is not not enough surface area on this sponge for new nitrite eating bacteria to populate? Am I fully staffed with nitrite bacteria eating workers?