A Question About Filter Bacteria and CO2

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Steven 1

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I have a ten gallon tank with a Fluval U2 filter. I have the media out. If I put the media in, will the bacteria that grow there increase the tank's amount of CO2 more than a few percentage points?

Thanks.
 

Slappy*McFish

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Not really. Filter bacteria are not significant producers of CO2.
 

Byron Amazonas

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I agree, it will be minimal. The bacteria (different sorts) that live in the substrate and break down organic waste are the main producers of CO2. Fish, plant and bacteria respiration also produces CO2 of course, but less that what occurs from the substrate--if it is basically left alone and is healthy. I am assuming plants are included, otherwise increasing CO2 would not be beneficial.

Byron.
 

Steven 1

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Yes, plants are part of the picture. I figured that the filter bacteria wouldn't be contributing a huge amount of CO2. The only benefit I can see in biological filtration is that there are more sites for bacteria to colonize and more Nitrogen can be processed. And sponges, etc., are good for filtering out particulate matter. But I'm not sure how big or small the difference in Nitrogen processed actually is.

With a fully planted tank, the plants' uptake of Nitrogen should take care of a good part of the Ammonia.
 

Byron Amazonas

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Yes, plants are part of the picture. I figured that the filter bacteria wouldn't be contributing a huge amount of CO2. The only benefit I can see in biological filtration is that there are more sites for bacteria to colonize and more Nitrogen can be processed. And sponges, etc., are good for filtering out particulate matter. But I'm not sure how big or small the difference in Nitrogen processed actually is.

With a fully planted tank, the plants' uptake of Nitrogen should take care of a good part of the Ammonia.
Yes. Many suggest not "encouraging" biological filtration in planted tanks. This is because the nitrifying bacteria are in competition with the plants for ammonia/ammonium. Studies have shown that plants are actually faster at taking up ammonia than the ammonia oxidizing bacteria (Nitrosomonas sp.). I engaged in a discussion with Tom Barr and others on one of the plant forums a while back, as to how much ammonia plants can take up, and if adding new fish would increase the ammonia to a mini-cycle as can occur in non-planted tanks. Tom said the amount of ammonia capable of being taken up by plants in a well planted tank is very high, and higher than would ever cause issues for fish unless something went very wrong. This has certainly been my experience; I set up new tanks with plants (floating are ideal for this) and fish and I have never had a "cycle" that could be measured.

Many will advocate planted tanks with no filter at all, and provided the planting is significant and the fish load moderate, there is no question that this works with no problems. So further proof that biological filtration need not be "encouraged." Obviously, nitrifying bacteria will colonize surfaces in the aquarium, so the presence or absence of any biological "filter" is not going to cause nitrogen-related problems for the fish, always provided everything is naturally balanced. I wouldn't overload the system.

Mechanical filtration, such as with sponges, filter floss, pads, etc, is beneficial in my opinion, but here again there are those who say this is not necessary. But having experiemented with a no-filter planted tank, it did seem that truly "clear" water required a sponge filter in a 10g tank. Mechanical filtration removes suspended particulate matter which can settle on plant leaves, inhibiting the exchange of nutrients, oxygen and CO2 that is essential for plants. And such filtration also results in a current which achieves this, plus it brings nutrients to plant leaves, and it provides more uniform temperature. But again, one can have a perfectly healthy natural aquarium without this too.

Nitrite and nitrate should never be issues in a planted tank, unless one or both of these is being artificially introduced via the water changes which is a very different set of issues. But assuming "pure" water from the tap, the ammonia being produced by fish and the breakdown of organics will easily be handled by the plants, though a tad will get taken up by the bacteria. But nitrite will be zero, and nitrate very low (less than 10 ppm is normal, many have zero nitrate).

Byron.
 

Steven 1

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I recall having read somewhere that in a river that was studied, the highest concentrations of bacteria (Nitrogen bacteria, I think) are where there are plants. I think that's why I have wanted the bacteria to be out of the filter, which would be mechanical only, and in the aquarium with (on) the plants. Sorry, no citation. In any case, it seems that the Nitrogen cycle bacteria would be left with a smaller population that would increase and decrease according to the availability of ammonia.

I think it is important to get the suspended particulate material out of the tank and decreasing the tank bio-load. I agree that mechanical means of filtration are good at this. For a while I was washing my filter sponge in tap water, exactly what everyone warns against, to keep mechanical filtration but not allow Nitrogen bacteria in the filter. I didn't notice any difference.

I'd be concerned about suspended particulate matter settling onto the plant leaves if there was no water movement, although I think it has been done. I'd love to get a chance to use the new Koralia powerheads, they seem so cool. I saw a beautiful video of a tank with a Koralia in it.
 

Byron Amazonas

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I recall having read somewhere that in a river that was studied, the highest concentrations of bacteria (Nitrogen bacteria, I think) are where there are plants. I think that's why I have wanted the bacteria to be out of the filter, which would be mechanical only, and in the aquarium with (on) the plants. Sorry, no citation. In any case, it seems that the Nitrogen cycle bacteria would be left with a smaller population that would increase and decrease according to the availability of ammonia.

I think it is important to get the suspended particulate material out of the tank and decreasing the tank bio-load. I agree that mechanical means of filtration are good at this. For a while I was washing my filter sponge in tap water, exactly what everyone warns against, to keep mechanical filtration but not allow Nitrogen bacteria in the filter. I didn't notice any difference.

I'd be concerned about suspended particulate matter settling onto the plant leaves if there was no water movement, although I think it has been done. I'd love to get a chance to use the new Koralia powerheads, they seem so cool. I saw a beautiful video of a tank with a Koralia in it.
I have always washed my canister filter media and the smaller-tank sponge filters under the tap; the latter are done weekly at every water change. But I know I have the plants and this causes no issues.

I also have a 20g tank planted that is used for quarantining new fish (not as a "hospital" tank, just a tank for new arrivals to monitor them for a few weeks). This tank runs permanently, and is planted fairly heavily with culls from the other tanks. It can run for several months with no fish, depending upon what I see locally and want. And during these periods, I do not use dechlorinator when I change half the water weekly. The plants have no issue with chlorine...it is actually one micro-nutrient, and the multitude of snails are not bothered by it. I do use dechlorinator if fish are present, as my tap water is very high in chlorine (but nothing else, luckily), you can often smell it.

I am not a fan of powerheads, having used them many years ago with undergravel filters. Basically, I don't want that much water circulation. This is in deference to my fish, most of which occur in quiet waters and do not appreciate currents. This becomes very obvious in a large tank like my 5-foot, in which I have a relatively strong current at one end because of the spotted woodcats that need it and they live in tunnels in a standing chunk of wood right under the filter outflow. But it is interesting to observe some species never venturing into that area, because of the current. My first priority is the fish; plants have to take the second seat. But you also don't want to much current as this is detrimental to plants, by bringing too much oxygen (which causes the plants to slow their uptake of nutrients) and by pushing the nutrients in the wsater column past the plants before they can take them up.

Byron.
 
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