Cycling, CO2 and PH question

[Bradders]

Here's a question for the experts out there.

Assume a constant of CO2 injection 24 hours of the day for this question.

As we are learning on this forum and more broadly, there are different types of nitrification "beneficial bacteria" that form in our filters and aquariums. Some favour growth in a pH of 6 to 8 (Nitrosomonas, Nitrosococcus), while some grow more in conditions (i.e. archaea, thaumarchaeot) that are more acidic—albeit research is saying that the latter grows slower than the higher pH bacteria.

Question: If you have a natural water pH of 6.5, and CO2 injection takes you to a pH of <=5.5 (the 1pH ish drop method), how does the BB 'work'? i.e. even though the natural water is 6.5, does injecting CO2 mean that the beneficial bacteria that form will be archaea, thaumarchaeot rather than Nitrosomonas or Nitrosococcus?

I am trying to work out whether the CO2 alters the water's "natural" chemistry to the point that BB also has to adapt. Or does BB formation/growth take into account the natural water pH position?

I hope that makes some sense. I felt a little lightheaded when writing it to be honest ....... 😱

Regards,
Brad

 

[dw1305]

Hi all,

Some favour growth in a pH of 6 to 8 (Nitrosomonas, Nitrosococcus),

mean that the beneficial bacteria that form will be archaea, thaumarchaeot rather than Nitrosomonas or Nitrosococcus?

I think the answer is that you don't have to worry about it, because the microbes

• <"that were though to occur in our filters">,
• which had been isolated from sewage sludge and
• need high ammonia and carbonate hardness.

don't actually occur in our filters. This is a quote from Tim Hovanec's marine article, it is well worth a read (I have a lot of time for Dr Hovanec).

........ Working in Ed’s lab, I developed molecular probes for Nitrosomonas europaea and closely related ammonia oxidizing bacteria (AOB) and Nitrobacter winogradskyi. I started applying them to samples from various sections of freshwater and marine aquaria (biofi lter material, substrate, and the bulk water). The results were unexpected—Nb. winogradskyi was not detected in any sample while N. europaea-type AOBs were only detected in marine aquaria. Furthermore, if I took a functioning freshwater aquarium and switched it to saltwater by only adding a synthetic salt mix, nitrifi cation halted—as evidenced by the sudden appearance of ammonia and then nitrite (so the tank was going through another cycling period). When I re-probed the tanks, once nitrifi cation became re-established, a positive signal for the presence of N. europaea-type AOBs was detected. Here was the fi rst solid evidence that ammonia oxidation was done by different organisms in freshwater aquaria compared to saltwater aquaria and Nitrobacter winogradskyi was not the nitrite-oxidizing bacteria in either situation .......

Tim Hovanec talks about this in both <"Bacteria Revealed"> & <"Tim Hovanec's "Nitrification in marine aquarium" article"> and we have <"Everyone is right ..."> etc.

...... A useful "filter" reference for this is: Barthelme, R et al (2017) <"Freshwater Recirculating Aquaculture System Operations Drive Biofilter Bacterial Community Shifts around a Stable Nitrifying Consortium of Ammonia-Oxidizing Archaea and Comammox Nitrospira" Front. Microbiol., 30>......

It was this research on nitrification that led us to contact <"Dr Hovanec">, and the <"Newton"> and <"Neufeld"> labs.

I'm not a betting man, but if I was? All my money is (on the nose) that "Biofilter Bacterial Community Shifts around a Stable Nitrifying Consortium of Ammonia-Oxidizing Archaea and Comammox Nitrospira" is the situation <"in our aquariums">.

I am trying to work out whether the CO2 alters the water's "natural" chemistry to the point that BB also has to adapt. Or does BB formation/growth take into account the natural water pH position?

I'd guess the added CO2 and lower pH doesn't make a lot of difference, it doesn't change the alkalinity of the water, you <"just have more D(T)IC">, in the form of extra CO2.

cheers Darrel

 

[Bradders]

Here is an interesting question to ponder., @dw1305 et al.

I am cycling my newly planted aquarium. It's been 15 days, and there is no ammonia, but nitrites are spiking between 1-2ppm. It's going through its process.

Now, in the new aquarium, with the aquarium soil and CO2 injection, the pH is between 6 and 6.5. My normal tap water is around 7.5-7.7, which is what my old aquarium runs at. There is basically a 1 to 1.5 difference in pH between the aquariums.

2 days ago, I took some very mature 20PPI foam from my Biomaster and placed that in my new Biomaster in the new cycling aquarium. That water has passed through the filter around 150 + times, but the nitrites are still 1-2ppm.

Question/observation: Shouldn't the mature foam full of bacteria not have eaten through the 1-2ppm nitrite in the last few days?

 

[hypnogogia]

Perhaps your’re producing nitrites as fast as they’re being broken down…

 

[Bradders]

Perhaps your’re producing nitrites as fast as they’re being broken down…

I thought that, but there isn't much of a high ammonia source. No inhabitants, just aquairium soil (Tropica) and plants.

 

[bazz]

Question/observation: Shouldn't the mature foam full of bacteria not have eaten through the 1-2ppm nitrite in the last few days?

I'm certainly no expert and stand to be corrected but just throwing it out there, is it possible that in the existing aquarium that once the bacteria/archaea had built up enough to deal with the high level of Nitrite at initial start-up would they then not reduce in number along with the reduction in Nitrite, and now have to catch up again, usually takes a week or so during the cycle?
Whatever, I still think it will cycle through a lot quicker than not having introduced the sponge.

 

[Bradders]

I'm certainly no expert and stand to be corrected but just throwing it out there, is it possible that in the existing aquarium that once the bacteria/archaea had built up enough to deal with the high level of Nitrite at initial start-up would they then not reduce in number along with the reduction in Nitrite, and now have to catch up again, usually takes a week or so during the cycle?

Yeah, I'm not sure about that. The old aquarium is moderately stocked, so expect the ammonia source to be relatively abundant. My thinking is that a good amount of Ammonia means that there need to be enough Nitrite critters to address.

I am scratching my head as to why Nitrite has not gone down in a couple of days once introducing the mature sponge!

 

[Bradders]

14 days later and the nitrites have gone down to just a shade of very light pink, but not white. I really expected the addition of the mature sponge to greatly decrease the nirtrites quickly! But its heading in the right direction.

 

[hypnogogia]

14 days later and the nitrites have gone down to just a shade of very light pink, but not white. I really expected the addition of the mature sponge to greatly decrease the nirtrites quickly! But its heading in the right direction.

How full of plants is the tank?

 

[Bradders]

How full of plants is the tank?

I would say it is pretty full, but not as packed as some people I have seen, as there is a large open space at the front.

The plants are growing (it has been 28 days from setup to now) - especially the ones at the back, but I am still suffering from a little surface oil, and I have not trimmed the plants yet as just wanted them to bed in. And I have not managed to kill the 4 Red Cherry Shrimp in there at current, which is a relief!

I was just surprised that the very mature foam did not stabilise everything (i.e. no nitrites) very quickly. The only difference between my two tanks is the pH level. The "fsih only" one sits around 7.7, but this one spends a lot of time between 6.6 and 6.0 as the Tropica Aquasoil is buffering to 7, and the CO2 can takes it down further. Testing the reagent on my fish only tank comes back transparent white, no matter how long I leave it. So I dont think its a test reading problem.

 

[Little]

Lovely tank btw. Like a stag emerging from the forest.

 

[hypnogogia]

The plants are growing (it has been 28 days from setup to now) - especially the ones at the back

I think 28 days should be sufficient. I'd be inclined not to fully trust the nitrite reading. Lovely looking tank and not a bit of diatom - well done!

 

[Bradders]

....... and not a bit of diatom - well done!

Well, there is some if you look hard enough! But I have been very lucky and quite surprised that I have not had major diatom/algae breakout.

I have not been busting the limits of CO2 and have been laser-focused on Dissolved Oxygen. (Thanks, @dw1305 —you hooked me onto that now!). Lights have been a steady 25%, and have only just upped the daily dosing of TNC by 20%. Slow and VERY steady has been my approach!

Of course - no fish yet, and I suspect that will add another 'dynamic' to the aquarium!

 

[dw1305]

Hi all,

have been laser-focused on Dissolved Oxygen. (Thanks, @dw1305 —

It isn't really me, I knew that <"scientists"> are primarily interested in <"dissolved oxygen">, either its <"effect on the biota"> (in relatively clean water) or just getting <"as much of it as possible"> into <"polluted water">.

".... Most pristine rivers will have a 5-day carbonaceous BOD below 1 mg/L. Moderately polluted rivers may have a BOD value in the range of 2 to 8 mg/L. Rivers may be considered severely polluted when BOD values exceed 8 mg/L. Municipal sewage that is efficiently treated by a three-stage process would have a value of about 20 mg/L or less. Untreated sewage varies, but averages around 600 mg/L in Europe and as low as 200 mg/L in the U.S., or where there is severe groundwater or surface water infiltration/inflow. The generally lower values in the U.S. derive from the much greater water use per capita than in other parts of the world.".

I'm a great believer in a picture being worth a thousand words and this is the <"activated sludge process"> at a sewage works. Dissolved oxygen is the metric that matters.

Photo by John Rostron, CC BY-SA 2.0, <File:Beckton STP, Activated Sludge Tank - geograph.org.uk - 1481906.jpg - Wikimedia Commons>

cheers Darrel