Fact or fiction? Plants kill beneficial bacteria.

Ian H

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Jan 24, 2005
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I have read in a number of posts recently that a heavily planted tank will starve the nitrifying bacteria in the filter.

I can't see that this can be true, following my new tank set-up where all of the substrate and water was changed. The Fluval 440 was out of commission for 18 hours and I had to set up my Eheim 2213 from my heavily planted tank.

The tank has been set up for over a week now and the ammonia and nitrate levels never have gone above zero. Unless this is a fishy miracle, or that bacteria can survive in a cold Fluval for 18 hours then my Eheim bacteria were very much alive and well. Incidentally the tank that the Eheim was attached to could not have been more heavily planted.

Ian
 

Laith

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Re: Fact or fiction? Plants kill beneficial bacteria.

The bacteria population density will be in direct relation to the availability of nutrients for them, in this case NH4 and NO2.

In a healthy, heavily planted tank the plants will suck up any NH4 before the bacteria really has a chance at it.

I'd therefore say that the bacteria population in heavily planted tanks is much lower than say a non-planted tank.
 

Ian H

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Re: Fact or fiction? Plants kill beneficial bacteria.

Laith said:
In a healthy, heavily planted tank the plants will suck up any NH4 before the bacteria really has a chance at it.

I'd therefore say that the bacteria population in heavily planted tanks is much lower than say a non-planted tank.
I'm not sure about that as a filter has a forced water flow against drift flow in the case of plants. Personally I would have thought that on that basis the bacteria get the first slice of cake.

Ian
 

fosteder

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Feb 3, 2005
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Re: Fact or fiction? Plants kill beneficial bacteria.

I have never "counted" the bacteria in my tank before or after planting it and I don't really plan to. ;)

You say your new tank is fully cycled? I would say you could test the theory pretty easily by removing all of you plants for a couple of days. If your tank goes into a mini-cycle then I would say your bacteria population is not as big as it once was prior to planting.
 

Ian H

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Re: Fact or fiction? Plants kill beneficial bacteria.

fosteder said:
I have never "counted" the bacteria in my tank before or after planting it and I don't really plan to. ;)

You say your new tank is fully cycled? I would say you could test the theory pretty easily by removing all of you plants for a couple of days. If your tank goes into a mini-cycle then I would say your bacteria population is not as big as it once was prior to planting.
Strangely enough I too have never counted the bacterial population.

I'm certainly not going to risk changing anything on my new tank as it contains 6 large discus. It is also not planted very heavily currently, the main plant population being giant vallis in effectively a low light none CO2 situation. Effectively the current plant growth is far less than in the tank the Eheim was originally attached to.

Ian
 

groovyfishguy

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Re: Fact or fiction? Plants kill beneficial bacteria.

I think the bacteria are pretty hardy little suckers. I bought a couple of old Bio-Wheel Filters from Mike Reed once that haven't been used in a while and I never had a spike of NH4 in the new set up tank. So in my experience at least on bio wheels some bacteria live a long time even when dry. :cool:
 

Tom Barr

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Re: Fact or fiction? Plants kill beneficial bacteria.

Well, the plants will reduce the population of bacteria, not starve them out of existence.

Bacteria are a good back up instead of algae.........
Bacteria also are present all over the plants, roots, and in the filter............not just all in the filter.

The poprus plant specific substrates also have large amounts of bacteria.
Where do all the fish feces go? Up or down into the substrate? Or to the filter?

So the bacteria will have the first dibs as well as the plant's roots/lower leaves.

The porous nature of substrates appears to be the main element in their efficacy rather than their nutrient constituents inside which will only last a relatively short time frame.

Regards,
Tom Barr
 

Ian H

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Jan 24, 2005
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Re: Fact or fiction? Plants kill beneficial bacteria.

I completely replaced the substrate, but as I used a mix of Levington cactus compost and commercial aquatic soil plus some broken expanded clay pebbles in the lower layer, I'm wondering that there may have been a natural build up of bacteria in this as I washed and drained it and left standing for 4 days.

Ian
 

Paul

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Jan 24, 2005
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Re: Fact or fiction? Plants kill beneficial bacteria.

This is a simlilar thought to one I have been wondering, has anyone tried turning off the filter and seeing if the plants will do all the work? I am guessing that you would have to have pump to give some water flow?
 

Ian H

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Re: Fact or fiction? Plants kill beneficial bacteria.

I did just that for 2 days after I moved the Eheim. I didn't have the desire to continue the experiment, but I set up the Eheim ecco filter just as a mechanical water polisher. No sign of any negative effects although I have drastically reduced the bio load.

Ian
 

Tom Barr

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Re: Fact or fiction? Plants kill beneficial bacteria.

More fish, more light, fewer plants= more need for a filter.
In general, (folks have tried this many times) the tanks tend to be no as robust over the long term without filters.

There is nothing wrong with them and they make good back ups.
Some say the NH4 is the issue, but heck, you can add NH4 from other sources than fish to see how much this is and what effect it has on plant growth, not much because you cannot add much without getting an algae bloom.

NH4 works fine and better than NO3, but this is much more the case for algae at the levels we typically might fine or are able to dose without killing all your fish.

Aquatic plants will use NH4 more than NO3 only if there is a substantial amount of NH4 present.

The growth diffwerence of NH4 vs NO3 does not outweigh the potential harm you can do.

See Green water............

Many folks that remove their filters often have clarity issues or get GW after some time.

Regards,
Tom Barr
 

Ian H

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Jan 24, 2005
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Re: Fact or fiction? Plants kill beneficial bacteria.

I like external filters, especially Eheims. I'll carry on running the Ecco I got with the other bits when I bought the Trigon tank. :)

Ian