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Will filter bacteria survive and function under 6 Ph?

Lindy

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Ayrshire, Scotland
Thanks very much for your replies.

My tank is running for almost two years now. Chocolate gouramis are in about a year and Vaillanti for few months. Problem is, that every time the pH drops bellow 5,5, I get stressed and do daily RO water changes until the pH rise again.
It´s common knowledge (between fishkeepers around here) that de-nitrifying bacteria stops working at pH bellow 6. (I don´t know if that is the true or not. I have read that they stop or that they don't.)

I just can´t use chocolates as the subjects for testing.

I am thinking of stopping to add any peat or oak leaves to the water, but it wouldn't be like their home anymore :)

I know i'm late to this party but what I'd like to suggest is that you prepare water in a container that has peat in it or are filtering through peat with an external. When it gets to the desired ph then use it to water change the tank the fish live in. This way you avoid the swings you are having. It was in this way I prepared water for my liquorice gourami while breeding them. I never added peat directly to their tanks.
 

Michal

Seedling
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I run both, filter and sump for a week now, and I'll continue for another two. Just to be sure.

I'm at RBG Kew next week, I'll try and get a shot of the water lily pool in the <"Princess of Wales Conservatory">. It used to have a great epiphyte branch above it, but it has gone now.

Well, that is amazing.

If you have plants they will take up any "spare" ammonia. For those who don't own Diana Walstad's <"book">, there is a useful summary in <"Plants vs Filters">.

From what I've just read I can understand that biofiltration by bacteria might be even bad for plants (for those preferring ammonium over nitrate). I've got around 15 plant species in my aquarium, but none of them is on the list in the summary. (I haven't got the book - yet). Does that mean that my plants prefer nitrate?
I also understand that if I keep aquarium filled with plants which prefer ammonium I don't need filtration. Just water movement.


Have a look a this article by Stephan Tanner <"Aquarium biofiltration">.

I think I know how substrate must be important in biofiltration. Once I changed all the substrate, keep plants, run the filters in barrel, keep most of the water, but after two weeks I had ammonia spike which killed third of the fish.
 

Michal

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I know i'm late to this party but what I'd like to suggest is that you prepare water in a container that has peat in it or are filtering through peat with an external. When it gets to the desired ph then use it to water change the tank the fish live in. This way you avoid the swings you are having. It was in this way I prepared water for my liquorice gourami while breeding them. I never added peat directly to their tanks.

Thank you Lindy.

Yes, I used to do that. Peat and RO water in a barrel.
Now just pure RO water straight to the aquarium. I change only 10% of water. I've got peat in a sump filter and oak leaves in the aquarium.
I don't worry about pH too much anymore (not after what I've read past few days).

Since you've got experience with breeding delicate fish I'd like to ask you something. If you be so kind?

My female chocolate has the eggs in her mouth now. I think it's fifth day. She is hiding all day, doesn't eat, just moving with her mouth sometimes. Do you think it's clever to take her out and put her into sump, where I keep cherry shrimps. I'm afraid that it will stress her, but I probably won't be able to find any fry and feed it. There are too many hiding places in the aquarium.
 

dw1305

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Hi all,
I also understand that if I keep aquarium filled with plants which prefer ammonium I don't need filtration. Just water movement.
I don't look on plants as an alternative to microbial filtration, I look on plants and microbes as two essential, synergistic, components of a whole system.
From what I've just read I can understand that biofiltration by bacteria might be even bad for plants (for those preferring ammonium over nitrate). I've got around 15 plant species in my aquarium, but none of them is on the list in the summary. (I haven't got the book - yet). Does that mean that my plants prefer nitrate?
Microbial biofiltration isn't bad for plants. Microbial nitrification produces nitrate (NO3-), and even though it looks like most plants will preferentially take up ammonium (NH4+), all plants will utilise any form of fixed nitrogen, including nitrite (NO2-).

Fixed nitrogen is always a scarce resource in nature, because it takes a lot of energy to split the stable triple bond of the N2 molecule to liberate two reactive nitrogen atoms, that can form biologically active compounds. Organisms have evolved to make use of any form of fixed nitrogen. For plants it takes less energy to take up ammonium, but a lot of fixed nitrogen is going to be NO3 and it will still be taken up and utilised.

cheers Darrel
 

Michal

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Thank you,

So it is about balance between microbial nitrification and plants. I am on the right path then :)
 

dw1305

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Hi all,
So it is about balance between microbial nitrification and plants. I am on the right path then
Yes you are.

As well as the direct nitrogen uptake by the plants they also provide additional oxygen and more niches for microbial colonisation (often from "leaky" roots), and these <"epiphytic nitrifiers"> are known to be particularly important in <"Constructed wetlands"> etc.

It is always plant/microbe filtration, a lot of the criticism of the cycling posts has ignored this, and unfavourably contrasted "filtration by plants" with "filtration by bacteria", as if they are mutually exclusive.
.....In addition, nitrogen in the ammonia form is not readily taken up by plants, so no matter how high the ammonia levels get in your fish tank; your plants will not be getting much nutrition from it.
This really p*sses me off, but on a lot of forums and <"web pages"> (where the quote above came from) there are statements that "plants don't take up ammonia, only nitrate" and are "really just an alternative to water changes", and don't have any "part to play in the important bits of biological filtration".
...Not quite accurate. While plants do consume some ammonia and nitrate, the amount of intake is puny. You’d have to cover every square inch of a 30 gallon fish tank just to take care of the ammonia produced by two tiny Neon Tetra. <"So the plants are irrelevant here.>"
Nothing could be further from the truth, and even the most cursory "Google" would <"provide plenty of evidence to the contrary">, but the same "facts" are continually re-cycled, and seem to have a life of their own.

cheers Darrel
 
Last edited:

Michal

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This really p*sses me off, but on a lot of forums and <"web pages"> (where the quote above came from) there are statements that "plants don't take up ammonia, only nitrate" and are "really just an alternative to water changes", and don't have any "part to play in the important bits of biological filtration".

I believe it could be annoying sometimes.

But for me personally, this website and information I found here, are extremely helpful.
 
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Plants are essential for fish well being as Darrel says, in many ways and in conjunction with the other type of filtration.

I was reading recently about phytoremediation of plants. You can find many papers about its positive affect, by different species of plants. Here is one about floaters.

http://www.tandfonline.com/doi/abs/10.1080/15226514.2016.1183567?journalCode=bijp20

"Phytoremediation of wastewater toxicity using water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes)"

This paper elucidates the phytoremediation potential of water hyacinth and water lettuce on the reduction of wastewater toxicity......

Results:

Phytoremediation reduced 58.87% of ammonium content, 50.04% of PO43−, 82.45% of COD and 84.91% of BOD. After 15 days of the experiment, metal contents in treated wastewaters decreased from 6.65 to 97.56% for water hyacinth and 3.51 to 93.51% for water lettuce tanks.
 
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