The myths and legends of anaerobic bacteria

[Daniel]

16 minutes ago, gardenman said:

When I hear people saying we all must do something because there's a scientific agreement on it, I cringe. As a general rule, the more scientists agree on something, the more likely it is they're wrong.

Ah yes! @gardenman well said!

There is nothing I have more belief in than science, and there is nothing more likely to be wrong than science. Scientist are like journalists. Thank goodness we have both, and both provide the best information we currently have. But don't mistake the best information we currently have for something that is reliable.

[L.W. Wetarm]

2 hours ago, OnlyGenusCaps said:

Dave has put together a good site there, and it's one of the best sources for well supported information in a hobby that is so often rife with half-truths, common knowledge, and personal anecdote.

I take it that you know who is behind Aquariumscience.org website? I like to know who is providing information so I can place some sort of credibility to it. As I research the website, I find a lot of message board chatter of a very negative nature. I don’t know that I buy all that he’s preaching but the information he gave on the fallacy of sintered glass, pumice, or lava as a denitrifying media was eye opening.  

[MJV Aquatics]

It strikes me a bit 'funny' that there's this ongoing quest for the dentrification holy grail...when fast growing plants and sufficient volume and frequency of partial water changes are all we really need. And I often have pondered if the focus on nitrates misses the fact that they keep bad company with other pollutant element types.

Now having written the above, I do have a couple of anoxic biocenosis clarification baskets in the 45g sump on my 110g stock tank (colony breeding red swordtails). But since the sump is full of growing water sprite and I do routine partial water changes, I can't really offer any conclusion regarding effectiveness. I also have another experiment that I've documented using a 4L loc 'n loc container with a Tom Aqualifter pump on my 60g. Again, I simply can't offer any testimonial (but again, I have floating plants and do routine weekly water changes)... I'm more interested in on-going high water quality rather than skimping on partial water changes. 🙂

[Anita]

On 3/27/2021 at 11:32 AM, Biotope Biologist said:

I can discuss this point a bit as I have done a lot of research of "water treatment" both in marine and freshwater systems.

 

So anaerobic bacteria as you know is bacteria that exists in the absence of oxygen. In fact oxygen is toxic to most species of anaerobic bacteria and will kill them. The benefits of anaerobic bacteria is that they produce some pretty awesome organic compounds as waste that especially plants love. Commonly they produce phosphorous, carbon dioxide, and sulfates. In a wastewater treatment faculty anaerobic in combination with aerobic bacteria are used to breakdown complex waste and turn it into, basically fertilizer. Both populations are considered a must for proper waste water recycling especially in combination with planted detention ponds.

Now in a home aquaria you have a closed system. Which makes utilizing the advantages of anaerobic bacteria, rather difficult. I have tried many times to incorporate anaerobic bacteria in both large industrial fish ponds and aquarium to limited success. Usually I try to separate anaerobic bacteria in their own sump or filter because disturbing the bed leads to oxygen and oxygen leads to mass die offs. The other concern is methane and carbon dioxide, if the gas exchange in the water is not monitored you can cause toxic stress to the gills of your fish.

When people have typically had issues with anaerobic bacteria in the aquarium, the scenario usually follows having deep unaerated substrate. Either you or your fish decide to disturb this bed releasing trapped CO2 and CH4 and killing the anaerobic bacteria causing a die off. This causes basically ammonia spikes.

 

EPA and department of Ecology are wonderful free resources for wastewater treatment here is a brief one:

https://www3.epa.gov/npdes/pubs/alagoons.pdf

ORD 💜

I second this excellent explanation of why it is a bit of a Sisphytic task (not to mention potentially hazardous to your aquarium residents) trying establish an anaerobic nitrogen cycle in a home aquarium. Wastewater treatment does not include keeping a bunch of fish in the containment lagoons. 😎

[Anita]

On 3/28/2021 at 7:58 PM, OnlyGenusCaps said:

This is a great and interesting topic!  I am an ecologist, and have colleagues who study nitrogen fluxes in aquatic systems.  It's very cool stuff whether you are talking about the reasons for the dead zone in the Gulf of Mexico or the processes in a home aquarium.

In terms of the anoxic, denitrification process, my suspicion is at the scale of the home aquarium it would simply be easier to do water changes or grow plants to reduce nitrates.  Indeed, I'm not certain it is possible to have denitrifying bacteria perform the function to any degree that would be beneficial (depending on stocking rates, of course). 

I'm trying to think of the best way to explain this, so please excuse me if I am fumbling a bit here.  For the most part, we try to keep O2 fairly high in aquarium water.  This is true not just in the display, but as we run it through filters.  Unless that oxygen is utilized by something, it doesn't tend to decrease dramatically (stays in equilibrium with normal solubility with the air).  Yes, loads of aerobic processes are going on in our tanks.  But to favor denitrification, it takes pretty low oxygen.  Denitrification is the least energetically efficient process in the aquarium "nitrogen cycle".  That means that the flow of oxygenated water to any given surface must be fairly low, or the O2 is too high and the process is no longer favored.  That can be achieved; however, think about if you had to achieve this with your typical biofiltration.  Think of the area you would need for beneficial bacterial growth if the flow had to remain low to every surface to achieve conversion of ammonium to nitrate.  So, while I think denitrification occurs in all aquaria, the area necessary to deplete the influx of nitrates would be massive, given the low flow rates that would be required to first deplete the oxygen.  After running through an effective denitrification reactor, the water would then need to be rapidly re-oxygenated or it would be lethal to the animals in the aquarium.

I am not saying that this is entirely impossible.  And as a scientist, I am always eager to be disproved by good data.  That said, I remain highly skeptical of the efficacy of such systems (even after watching videos made by certain doctors).  Additionally, I am not certain that an effective denitrification reactor would be a better option than simply changing your water regularly, or growing plants (even if only in a refugium).  Yes, plants will largely have an affinity for ammonium over nitrates, but they will scavenge nitrates quite effectively (which plants are best for this purpose in a freshwater system, remains an open question for me). 

ORD 💜 This is also great. Not fumbling at all. Thanks!

[Anita]

12 hours ago, Biotope Biologist said:

This is one of the wonderful things about science. We may state things as matter of fact, but we never are truly certain and hope to be proven wrong. This is why we constantly test each other's hypothesis. Even if it has been proven 200 times or 200,000 times all it takes is one experiment with good controls to throw a wrench into what we assumed was true from the initial experiment.

What fun reading this has been! Thanks @Will Billy for starting this thread and @OnlyGenusCaps @Biotope Biologist for your expertise! And @gardenman for your perceptive eye. 🤓🥼⚛️🔬

[Anita]

As another former basic research life sciences lab tech, I believe we scientists are prone to falling into the trap of over-reductive thinking. A professional pitfall, so to speak.

Here's what I mean by that. Let's say we are trying to improve the efficiency of the nitrogen cycle by boosting the anaerobic bacterial contribution. To produce credible results, an experiment must focus on some limited aspect of the anaerobic bacterial cycle, in order to create controlled conditions that eliminate as many variables as possible. Then tunnel vision kicks in and the tail starts wagging the dog. We start thinking that the BEST or ONLY solution for improving denitrification is via anaerobic bacteria, in fact, using one particular sub-species of bacteria! Haha! With our laser-sharp vision focused on revealing "the truth," we forget the larger goal, which is to improve the efficiency of the nitrogen cycle. We forget that in the real world, the anaerobic cycle never works in isolation. 

As we have seen from the many responses in the thread, the nitrogen cycle has many moving parts, aerobic and anaerobic. 😎

Edited March 30, 2021 by Anita

[Biotope Biologist]

14 minutes ago, Anita said:

As another former basic research life sciences lab tech, I believe we scientists are prone to falling into the trap of over-reductive thinking. A professional pitfall, so to speak.

Here's what I mean by that. Let's say we are trying to improve the efficiency of the nitrogen cycle by boosting the anaerobic bacterial contribution. To produce credible results, an experiment must focus on some limited aspect of the anaerobic bacterial cycle, in order to create controlled conditions that eliminate as many variables as possible. Then tunnel vision kicks in and the tail starts wagging the dog. We start thinking that the BEST or ONLY solution for improving denitrification is via anaerobic bacteria, in fact, using one particular sub-species of bacteria! Haha! With our laser-sharp vision focused on revealing "the truth," we forget the larger goal, which is to improve the efficiency of the nitrogen cycle. We forget that in the real world, the anaerobic cycle never works in isolation. 

As we have seen from the many responses in the thread, the nitrogen cycle has many moving parts, aerobic and anaerobic. 😎

It is interesting that you talk about the over-reductive thinking. Lately, I have been reading books about how to do ecological research effectively. In college, we touched on it a bit, but ultimately our research topics became narrow to make life easier and not have so many variables. 

 

I have always wondered how do you study the forest for the trees and the trees for the forest so to speak at the same time. Because when you do research on an ecosystem, like the home aquarium, the task seems quite daunting to separate all of the variables that go into it. From the physical level of mechanical processes such as filter speed and flow rate and temperature and thermodynamics, to the chemical processes such as the nitrogen cycle, oxygen saturation, and organic wastes, to the biological inputs such as fish and bacteria and plants. Then you have how all of that interacts with each other and it's a wonder how anyone has the patience to build an aquarium in the first place.

 

In Washington state we always talk about the Salmon and the Orcas. Someone has to save them, and the public wants a silver bullet, but the truth is there are SO MANY variables. And now thanks to Laurie Weitkamp and her fellow Oregon State colleagues we know that Lamprey populations are in severe decline and yet another variable to add to the mix as to not only Salmon and Orca populations but creek and river ecosystems as a whole. I got off topic, but I encourage more people to look at her research and watch her talks if they are interested. Lamprey are adorable and awesome.

 

Maybe @OnlyGenusCaps has more insight into ecology research.

[Will Billy]

26 minutes ago, Anita said:

As we have seen from the many responses in the thread, the nitrogen cycle has many moving parts, aerobic and anaerobic. 😎

Your entire response hits the nail on the head, but the section i quoted deserves a second pause for thought. Unbeknownst to me, i guess that was the all encompassing goal of my experiment. Through aerobic, anoxic, anaerobic, plants, routine water changes, and traditional filtration be it bio, chemical, and mechanical, i was hoping for that perfect balance. Focusing on the elusive anaerobic part, because its the apparently hardest to achieve. My experiment may have been blinded by not having all the other moving parts to contribute to growing that 1 said elusive part. The experiment could therefore be flawed not for just the aforementioned posts above, but flawed just on the theory of testing for anaerobic activity by itself without any of the other moving parts you so elegantly put it. Good food for thought.    

[Anita]

Just now, Biotope Biologist said:

It is interesting that you talk about the over-reductive thinking. Lately, I have been reading books about how to do ecological research effectively. In college, we touched on it a bit, but ultimately our research topics became narrow to make life easier and not have so many variables. 

I have always wondered how do you study the forest for the trees and the trees for the forest so to speak at the same time. Because when you do research on an ecosystem, like the home aquarium, the task seems quite daunting to separate all of the variables that go into it. From the physical level of mechanical processes such as filter speed and flow rate and temperature and thermodynamics, to the chemical processes such as the nitrogen cycle, oxygen saturation, and organic wastes, to the biological inputs such as fish and bacteria and plants. Then you have how all of that interacts with each other and it's a wonder how anyone has the patience to build an aquarium in the first place.

In Washington state we always talk about the Salmon and the Orcas. Someone has to save them, and the public wants a silver bullet, but the truth is there are SO MANY variables. And now thanks to Laurie Weitkamp and her fellow Oregon State colleagues we know that Lamprey populations are in severe decline and yet another variable to add to the mix as to not only Salmon and Orca populations but creek and river ecosystems as a whole. I got off topic, but I encourage more people to look at her research and watch her talks if they are interested. Lamprey are adorable and awesome.

Maybe @OnlyGenusCaps has more insight into ecology research.

ORD 💜 

Purely speculative on my part, but I feel as though fractals mathematicians were instrumental in getting scientists to start thinking more holistically about complex systems. E.g., ecology, Earth sciences, etc.

[anewbie]

1 hour ago, MJV Aquatics said:

It strikes me a bit 'funny' that there's this ongoing quest for the dentrification holy grail...when fast growing plants and sufficient volume and frequency of partial water changes are all we really need. And I often have pondered if the focus on nitrates misses the fact that they keep bad company with other pollutant element types.

Now having written the above, I do have a couple of anoxic biocenosis clarification baskets in the 45g sump on my 110g stock tank (colony breeding red swordtails). But since the sump is full of growing water sprite and I do routine partial water changes, I can't really offer any conclusion regarding effectiveness. I also have another experiment that I've documented using a 4L loc 'n loc container with a Tom Aqualifter pump on my 60g. Again, I simply can't offer any testimonial (but again, I have floating plants and do routine weekly water changes)... I'm more interested in on-going high water quality rather than skimping on partial water changes. 🙂

I don' tthink this is true. My 20L stayed at 1ppm nitrate with no water changes for 4 months my 29 stayed at 20 nitrate even with 50% water changes twice a week. I wonder which tank had more fishes and plants....

[Anita]

3 minutes ago, Will Billy said:

Your entire response hits the nail on the head, but the section i quoted deserves a second pause for thought. Unbeknownst to me, i guess that was the all encompassing goal of my experiment. Through aerobic, anoxic, anaerobic, plants, routine water changes, and traditional filtration be it bio, chemical, and mechanical, i was hoping for that perfect balance. Focusing on the elusive anaerobic part, because its the apparently hardest to achieve. My experiment may have been blinded by not having all the other moving parts to contribute to growing that 1 said elusive part. The experiment could therefore be flawed not for just the aforementioned posts above, but flawed just on the theory of testing for anaerobic activity by itself without any of the other moving parts you so elegantly put it. Good food for thought.    

ORD 💜 
Personally and for me, successfully caring for living organisms requires both science (logic) and art (intuition). 🐟🐌🌿🦐

[Frank]

14 hours ago, Will Billy said:

I hate to admit it bu the results my test is showing, is starting to fall in line with the article @L.W. Wetarm posted. The 5 gallon buckets had a bit of initial improvement but have since leveled off. The 55 gallon tank however did show a significant initial improvement (likely due to larger filtration media volume), but it is beginning to level off too. I always knew plant would absorb nitrates, i was just hoping to assist them with bacteria and sorta of meet them in the middle. So far my experiment isnt producing the results i had hoped for. Its still early in the experiment, and im not giving up just yet, but its looking like adding more plants is the only way to go to reduce water changes and or water change volume. Again it was never my wish to remove water changes entirely, i was hoping to find a mechanism to reduce frequency and volume. Not looking good folks, but ima hang in there and continue to report my findings. 

I'm confused. Maybe I'm not following properly?

It looks, to me, that you have had the desired result. Is the disappointment only with the degree of improvement?

[MJV Aquatics]

3 hours ago, anewbie said:

I don' tthink this is true. My 20L stayed at 1ppm nitrate with no water changes for 4 months my 29 stayed at 20 nitrate even with 50% water changes twice a week. I wonder which tank had more fishes and plants....

Since there's no test kit I know of that measures down to 1ppm, I question the results. But the point I was making is we tend to think that aquarium pollution is nitrates alone and that's just not the case. Besides, if we look at nature, fresh water is renewed by rains and snow melt ALL the time...creeks, streams, and rivers that run constantly to the sea! The output of the Amazon river is so great that fresh water can be collected 12 miles out at sea. Our confined aquarium creatures live in varying degrees of polluted water and the hobbyist needs to act like nature and make the rain to provide the highest possible water quality. Fast growing plants and deep sand, or anoxic facultative bacteria can all assist....but nothing beats diluting the pollution with fresh, clean water!

[anewbie]

2 hours ago, MJV Aquatics said:

Since there's no test kit I know of that measures down to 1ppm, I question the results. But the point I was making is we tend to think that aquarium pollution is nitrates alone and that's just not the case. Besides, if we look at nature, fresh water is renewed by rains and snow melt ALL the time...creeks, streams, and rivers that run constantly to the sea! The output of the Amazon river is so great that fresh water can be collected 12 miles out at sea. Our confined aquarium creatures live in varying degrees of polluted water and the hobbyist needs to act like nature and make the rain to provide the highest possible water quality. Fast growing plants and deep sand, or anoxic facultative bacteria can all assist....but nothing beats diluting the pollution with fresh, clean water!

Have you ever used the Salfifert test kit ? Look I might be a newbie but i'm not totally clueless. The argument you make is one repeated by many verbatium. There is some fallacy in the argument and some accuracy. I never said water changes were bad or pointless or should be avoided -  just that under certain circumstances the nitrate will stay very low despite high fish load - most likely due to bacteria eating the nitrate. Also while there are benefits to water changes it is a mistake to suggest that water changes somehow imitates nature  - this is simply not the case.

[Will Billy]

5 hours ago, Frank said:

looks, to me, that you have had the desired result. Is the disappointment only with the degree of improvement?

Sorta, the buckets in the experiment got an ever so slightly lighter shade of red and then stoped. There appears, so far in the experiment no continual nitrate removal. I was hoping for a continuous solution to assist plants, filters, and water changes. My assumption at this point is that nitrates became trapped, and not removed, until i can give the experiment enough time to prove otherwise i wont jump to any conclusions just yet. 

[OnlyGenusCaps]

Wow, miss a little, miss a lot here on the CARE forum.  So much for Cory's desire for work life balance. 😉  There were so many great comments here, and I'm hoping to add to the conversation.  That said, I just finished writing and posting an ecology exam for my students, so I'm a bit fried.  If you could all excuse the subsequent minor (and major?) typos that follow, I sure would appreciate it.

11 hours ago, gardenman said:

Yeah. Astronomers knew all about the rings of Saturn until Voyager flew by and got some close up photos that proved nearly all of the "known" stuff wrong. When I hear people saying we all must do something because there's a scientific agreement on it, I cringe. As a general rule, the more scientists agree on something, the more likely it is they're wrong.

Things like aquariums have so many variables that it's hard to come to a firm conclusion on just about anything. Even something simple like "How much ammonia is toxic to a fish?" has a lot of "it depends" involved. Water temperature, pH, and more can all affect it and not just a little, but a lot. A low pH tank kept cold can have an insanely high amount of ammonia with no harm to the fish. A higher pH tank at a warmer temp can kill a fish at a tenth of that level.

My 50 gallon tank is horrifically overcrowded by any objective measure, but it's doing fine. Why? It's been set up and running for about forty years with the same substrate and many of the same decorations/plants. It's housed an Oscar, a very large Midas Cichlid, some large goldfish, and now a vast school of Neon swordtails and super red bristlenose plecos. All lived long and happy lives in that tank. Is it a magic tank? Probably not. It's likely that the substrate and tank decor have built up such a massive load of bacteria over the years that it can handle anything. I don't disturb it and just leave it be and everyone's happy. 

Your example of Saturn's rings is exactly what I love about science.  When presented with new information, science incorporates it and adapts.  This gets portrayed in the same light as a "flip-flopping" politician with things like "those darn scientists don't seem to stick to an answer".  But that's the point.  Discovery doesn't stop.  Imagine if we demanded no more information be incorporated into our understanding.  Physicians would still be treating the "humours" of the body.  We'd never have gone into space.  The industrial revolution?  Forget it.  That scientists learn from new information moves us all forward.  I assure you, this is a feature not a bug.

Things scientists generally agree on: a dropped object will be accelerated toward the Earth, the Earth is round and goes round the Sun, our bodies use DNA to encode information that is translated to build our bodies, elephants are mammals...  The list goes on.  Generally speaking, if scientists agree on something, it is the best current understanding we have built based on the available information.  Does this mean scientists as a group know everything?  Absolutely not.  That continued discover bit from earlier.  And additionally, there are fields in which many of the scientists seem to have difficulty in separating what the science tells us is happening, and what they as citizens think we should do with this information.  That lack of clear distinction doesn't help anyone.  But be assured that there are powerful incentives for scientists not to agree.  Indeed scientists are about the most argumentative group around.  If you want to get fame and fortune (or really a scientific publication and a look in at a grant), then the best way to do that is to falsify an established dogma.  Scientists want to prove other scientists wrong.  They don't want to agree.  They are forced to by data.

Those are great points about the complexity involved in even a relatively simple setup like a home aquarium!  And I think pH is a wonderful example of it.  For me complexity doesn't mean that I won't continue trying to figure out what is happening.  I can see that is true for you as well.  I'm glad to be in such good company on that!

10 hours ago, L.W. Wetarm said:

I take it that you know who is behind Aquariumscience.org website? I like to know who is providing information so I can place some sort of credibility to it. As I research the website, I find a lot of message board chatter of a very negative nature. I don’t know that I buy all that he’s preaching but the information he gave on the fallacy of sintered glass, pumice, or lava as a denitrifying media was eye opening.  

I'd say I sort of to knowing him.  It's not like our families go on picnics together.  But I do know who he is and correspond.  I'm never comfortable divulging personal information about someone that they have not made publicly and easily available themselves.  That said, I do take your point about sources.  I've encouraged him to include his references, as I think that would help.

I'm not surprised there would be negative opinions.  When "common knowledge" is challenged there is a tendency for upset.  Of course, if there were references people could address the studies directly.  Plus, he's not always tactful.  I've encouraged him to take a more generous view in some of his statements, and he has softened the language in those cases a bit.

8 hours ago, MJV Aquatics said:

It strikes me a bit 'funny' that there's this ongoing quest for the dentrification holy grail...when fast growing plants and sufficient volume and frequency of partial water changes are all we really need. And I often have pondered if the focus on nitrates misses the fact that they keep bad company with other pollutant element types.

I absolutely get why people want to get rid of nitrates.  It's the human desire to strive to perfect things.  To advance.  To make progress.  And a smidge of laziness thrown in, if we are talking about me at least.

7 hours ago, Anita said:

As another former basic research life sciences lab tech, I believe we scientists are prone to falling into the trap of over-reductive thinking. A professional pitfall, so to speak.

Here's what I mean by that. Let's say we are trying to improve the efficiency of the nitrogen cycle by boosting the anaerobic bacterial contribution. To produce credible results, an experiment must focus on some limited aspect of the anaerobic bacterial cycle, in order to create controlled conditions that eliminate as many variables as possible. Then tunnel vision kicks in and the tail starts wagging the dog. We start thinking that the BEST or ONLY solution for improving denitrification is via anaerobic bacteria, in fact, using one particular sub-species of bacteria! Haha! With our laser-sharp vision focused on revealing "the truth," we forget the larger goal, which is to improve the efficiency of the nitrogen cycle. We forget that in the real world, the anaerobic cycle never works in isolation. 

As we have seen from the many responses in the thread, the nitrogen cycle has many moving parts, aerobic and anaerobic. 😎

I think I see where you are coming from here (correct me if I am wrong).  It's like the simplified expectations in the run up to, and for a time after, the human genome project.  Back when geneticists were hoping to find a gene for everything.  Tall?  This is the gene that made you that way.  Brown eyes?  Here is your gene?  Like keeping fish?  We've found the gene for that too!  Of course, in reality it is far, far more complex.

That said, you need to reduce the influencing factors to get at what components do.  It's not the most efficient way forward, but when you are pushing into the unknown, sometimes you have to feel your way in the dark.  You begin by isolating, and then you should come back around to add factors back in to get a more holistic view.  Learn if the components are additive, or exponential, etc.  But, I still remember back when I was a student learning how to do mathematical modeling, my advisor told me that you always assume it is a linear relationship first.  Why?  Because it's easiest, and you can always add complexity.

6 hours ago, Biotope Biologist said:

Maybe @OnlyGenusCaps has more insight into ecology research.

@Biotope Biologist You are going to get my train of thought to jump the tracks onto the garden path (if I may mix my metaphors).  This thread has been so nicely on topic, I hope I don't seem inconsiderate if I decline here.  I would be happy to talk about ecological research, and how complex systems are studied, etc.  But I don't want to distract from this wonderful thread.

6 hours ago, Will Billy said:

Your entire response hits the nail on the head, but the section i quoted deserves a second pause for thought. Unbeknownst to me, i guess that was the all encompassing goal of my experiment. Through aerobic, anoxic, anaerobic, plants, routine water changes, and traditional filtration be it bio, chemical, and mechanical, i was hoping for that perfect balance. Focusing on the elusive anaerobic part, because its the apparently hardest to achieve. My experiment may have been blinded by not having all the other moving parts to contribute to growing that 1 said elusive part. The experiment could therefore be flawed not for just the aforementioned posts above, but flawed just on the theory of testing for anaerobic activity by itself without any of the other moving parts you so elegantly put it. Good food for thought.    

If I may, I think your experiment was/is great.  You are trying to isolate the potential contribution of denitrifying bacteria.  If you included all of those other things, you'd need to parse out their contribution to the process, which would be far more involved.  I think it's great that you decided to do this experiment, share your thoughts and findings.  I've been enjoying the conversation is started immensely.  So thank you!

Moreover, I know I am new around here, but I'm so impressed with the thoughtful and constructive contributions from so many people, particularly to a topic that many would find to be arcane.  I'm enjoying my time here.  Thank you all!

[Anita]

2 hours ago, OnlyGenusCaps said:

Wow, miss a little, miss a lot here on the CARE forum.  So much for Cory's desire for work life balance. 😉  There were so many great comments here, and I'm hoping to add to the conversation.  That said, I just finished writing and posting an ecology exam for my students, so I'm a bit fried.  If you could all excuse the subsequent minor (and major?) typos that follow, I sure would appreciate it.

[text deleted]

Moreover, I know I am new around here, but I'm so impressed with the thoughtful and constructive contributions from so many people, particularly to a topic that many would find to be arcane.  I'm enjoying my time here.  Thank you all!

Haha, no worries. Thank YOU for adding to such an interesting conversation. And Welcome Back! 🤩

[BenA]

11 hours ago, anewbie said:

it is a mistake to suggest that water changes somehow imitates nature  - this is simply not the case.

Why do you say this?

Thanks

[gardenman]

36 minutes ago, BenA said:

Why do you say this?

Thanks

I'm not anewbie, but there are some fairly big differences. When humans do water changes it's typically with treated water containing some form of chlorine/chloramine, fluoride, and other unnatural chemicals, and typically tries to match the pH and temperature of the water in the aquarium so we don't shock the fish. Rainfall is different. It's typically cooler than the pre-existing water, has nearly no mineral content, tends to be a bit acidic, and comes in varying volumes from minimal to flood inducing. Rainfall oxygenates the water by the act of falling into the water. It also tends to introduce an abundance of fresh food into the water supply by washing insects, fruits, and other food sources into the water.  Even the heaviest of rainfall is less than a fifty percent water change we often carry out in our tanks. Doubling the volume of the Amazon would take a heck of a lot of rain. 

Water changes aren't bad, but they're not "natural" or simulate nature. They're a means to try and give our fish the best possible life experience in an unnatural setting. If you were to try and truly simulate nature, you'd have to use water more closely matching natural rainfall chemically, inject it in a rainfall like manner with rain droplets falling into the water, often for hours on end accompanied by the changes in light that comes with storms. The water added would be closely matching the temperature of rainfall in their native region. Food sources would be added during the process to simulate bugs and food washing into the natural water from a rainstorm. Any lack of minerals in the water would have to be compensated for by a mineral rich substrate.

We often trick fish into spawning by doing large water changes with cooler water to simulate a heavy rainfall. Some then add extra food so the parent fish will think there's plenty of food for their fry. These are ways we try to trick the fish into spawning and for some fish it works. For many it doesn't. All fish spawn in the wild or they'd be extinct. Many fish don't spawn in captivity despite our best efforts to trick them into spawning. Why? Because we're not doing a good enough job of simulating nature. There's a spawning trigger of some sort that we haven't figured out just yet. Even at our best, we're a very poor imitation of nature. 

[anewbie]

I would add one (of many) additional information to @gardenmananswer. When water flows down the stream it has the substance of what is upstream (fish, bacteria, ...., and unfortunately pollution when polluted) which is very different than when we siphon water out of a tank and add treated water. Don't take me wrong I think changing water is useful for the fish health but ...

[Anita]

4 hours ago, gardenman said:

I'm not anewbie, but there are some fairly big differences. When humans do water changes it's typically with treated water containing some form of chlorine/chloramine, fluoride, and other unnatural chemicals, and typically tries to match the pH and temperature of the water in the aquarium so we don't shock the fish. Rainfall is different. It's typically cooler than the pre-existing water, has nearly no mineral content, tends to be a bit acidic, and comes in varying volumes from minimal to flood inducing. Rainfall oxygenates the water by the act of falling into the water. It also tends to introduce an abundance of fresh food into the water supply by washing insects, fruits, and other food sources into the water.  Even the heaviest of rainfall is less than a fifty percent water change we often carry out in our tanks. Doubling the volume of the Amazon would take a heck of a lot of rain. 

Water changes aren't bad, but they're not "natural" or simulate nature. They're a means to try and give our fish the best possible life experience in an unnatural setting. If you were to try and truly simulate nature, you'd have to use water more closely matching natural rainfall chemically, inject it in a rainfall like manner with rain droplets falling into the water, often for hours on end accompanied by the changes in light that comes with storms. The water added would be closely matching the temperature of rainfall in their native region. Food sources would be added during the process to simulate bugs and food washing into the natural water from a rainstorm. Any lack of minerals in the water would have to be compensated for by a mineral rich substrate.

We often trick fish into spawning by doing large water changes with cooler water to simulate a heavy rainfall. Some then add extra food so the parent fish will think there's plenty of food for their fry. These are ways we try to trick the fish into spawning and for some fish it works. For many it doesn't. All fish spawn in the wild or they'd be extinct. Many fish don't spawn in captivity despite our best efforts to trick them into spawning. Why? Because we're not doing a good enough job of simulating nature. There's a spawning trigger of some sort that we haven't figured out just yet. Even at our best, we're a very poor imitation of nature. 

ORD 💜. Especially the last bit, "Even at our best, we're a very poor imitation of nature." We do our best and pray for the rest! 😁 

[Anita]

3 hours ago, anewbie said:

I would add one (of many) additional information to @gardenmananswer. When water flows down the stream it has the substance of what is upstream (fish, bacteria, ...., and unfortunately pollution when polluted) which is very different than when we siphon water out of a tank and add treated water. Don't take me wrong I think changing water is useful for the fish health but ...

ORD 💜

[BenA]

6 hours ago, gardenman said:

I'm not anewbie, but there are some fairly big differences. When humans do water changes it's typically with treated water containing some form of chlorine/chloramine, fluoride, and other unnatural chemicals, and typically tries to match the pH and temperature of the water in the aquarium so we don't shock the fish. Rainfall is different. It's typically cooler than the pre-existing water, has nearly no mineral content, tends to be a bit acidic, and comes in varying volumes from minimal to flood inducing. Rainfall oxygenates the water by the act of falling into the water. It also tends to introduce an abundance of fresh food into the water supply by washing insects, fruits, and other food sources into the water.  Even the heaviest of rainfall is less than a fifty percent water change we often carry out in our tanks. Doubling the volume of the Amazon would take a heck of a lot of rain. 

Water changes aren't bad, but they're not "natural" or simulate nature. They're a means to try and give our fish the best possible life experience in an unnatural setting. If you were to try and truly simulate nature, you'd have to use water more closely matching natural rainfall chemically, inject it in a rainfall like manner with rain droplets falling into the water, often for hours on end accompanied by the changes in light that comes with storms. The water added would be closely matching the temperature of rainfall in their native region. Food sources would be added during the process to simulate bugs and food washing into the natural water from a rainstorm. Any lack of minerals in the water would have to be compensated for by a mineral rich substrate.

We often trick fish into spawning by doing large water changes with cooler water to simulate a heavy rainfall. Some then add extra food so the parent fish will think there's plenty of food for their fry. These are ways we try to trick the fish into spawning and for some fish it works. For many it doesn't. All fish spawn in the wild or they'd be extinct. Many fish don't spawn in captivity despite our best efforts to trick them into spawning. Why? Because we're not doing a good enough job of simulating nature. There's a spawning trigger of some sort that we haven't figured out just yet. Even at our best, we're a very poor imitation of nature. 

Thank you. Thoughtful answer. 

[MJV Aquatics]

On 3/30/2021 at 8:13 PM, anewbie said:

just that under certain circumstances the nitrate will stay very low despite high fish load - most likely due to bacteria eating the nitrate. Also while there are benefits to water changes it is a mistake to suggest that water changes somehow imitates nature  - this is simply not the case.

It is only anoxic or anaerobic bacteria that can convert nitrates into nitrogen gas and these conditions are difficult to achieve and maintain in the highly oxygenated fresh water aquarium. I've tried for a very long time with deep sand, Seachem Matrix/De*Nitrate filters with low flow, and Dr. Kevin Novak's Anoxic Biocenosis Clarification Baskets and just never see significant nitrate reduction. The very best approach seems to be with fast growing floating plants and routine partial water changes. 🙂

Routine periodic partial water changes, like rain and/or snow melt do imitate nature as polluted water is replaced by fresh, clean water. In the very best system, fresh water would be constantly added as used water drains away.