A Challenging Question on Bacteria . . .

[Wy Renegade]

As I sat last evening in my favorite lounge chair, sipping my favorite beverage, contemplating one of several aquariums, and enjoying the comforts of life a question began to stir around in this old head of mine. A question on bacteria.

Now most of us think of ourselves as fish keepers, and in truth we are, yet in order to successfully keep an aquarium, we actually keep much more than fish, sometimes by choice, sometimes because of necessity. One of those things that we keep by necessity is bacteria, bacteria are required to convert fish waste containing ammonia into nitrites and ultimately into nitrates. Some, like cyanobacteria, are able to trap nitrogen gas and convert it into nutrientients (ammonia, or nitrite, or nitrates) for assimilation and growth by plants. The most ubiquitous form of life on the planet, bacteria are tiny in size and are found on almost every surface on the planet including your skin. Hundreds of thousands of these tiny organisms can fit on the tip of a pin, and a single bacterium reproducing every 20 minutes can produce 5,000 billion billion offspring in a single day.

One of the comments that I run across daily on the this forum, is that "most of the beneficial bacteria in are aquarium are found in our filter media". In fact, I've seen it so often that I actually found myself parroting it just the other day. I've also seen comments like "bacteria don't live in the water column" or "significant numbers of bacteria are not found in the substrate."

Now some of these comments, I know for a fact are untrue. I've personally grown many, many cultures plates using aquarium water from both salt and freshwater tanks, and I can assure you based on the results that bacteria are indeed found in the water column in great numbers. Now are these bacteria the ones that we desire, thats a whole different question, but based on my past experiences seeding tanks, I'm prepared to argue that indeed some of them are.

Other comments, I have to question. Lets look at the one about the majority of beneficial bacteria being found in our filter media. If bacteria can in fact occupy almost any surface area, then they should by default be found on all the surface areas within our tank. Excluding only those that for some reason or other are unfavorable to their existence. Now the bacteria that we desire to keep in our aquariums are found natural in streams, lakes, and ponds, and in these systems, the bacteria are found on the substrate. There is no giant filter anywhere that is filtering the world's water supply. If in fact they can survive in the substrate of the natural environment, then it stands to reason to me, that they can also by default survive in the substrate (at least the upper layers which contain oxygen) in our aquariums. If in fact this is true, then the availability of bacteria by count, becomes a question of viable space.

So, if I take my aquaclear filter and I compare the available surface area within the media within it, how does that compare to the available surface area in my substrate? Even if I'm willing to concede that the ceramic media and the sponges are significantly more porous than the substrate in question and I limit myself to the top inch or so of substrate within the tank, by hammering the ceramic media into powder and cutting the sponge down into 1/4" strips, I'm still forced to concede that there is significantly more viable surface area within the substrate then there is within my filter.

By default then, I am forced to conclude that in fact there should be significantly more bacteria of the desired type found on the substrate within our aquariums than there is in the filter media.

Now are these bacteria on the substrate as easily transfered from aquaria to aquaria as is the bacteria on the filter media, probably not. Is it possible to transfer this bacteria? Yes obviously, as we often talk of seeding a new aquarium by using substrate or decorations from a new one. So if its possible, then theoretically, if a person moved enough substrate, it would be possible to set up a brand new aquarium with enough viable, beneficial bacteria already in it, that that aquarium would in fact be "cycled" at set-up.

Please understand that I'm not advocating this for new aquariumists, I'm simply possing the questions for discussion amongst those of us with a bit more experience.

As always, I'm willing to be convinced that I'm wrong, so if you feel that I am, then please, by all means . . . convince me.

Please keep in mind that controversial discourse between educated individuals is never an argument, but just a spirited exchange of ideas and keep it civil. Thanks all for reading my rambling thoughts, even if you choose not to participate in the discussion.

 

[jcolon]

A very interesting post and I'm excited to read responses!

 

[LyndaB]

Very interesting post..... thanks for sharing.

 

[BigJim]

Based on extensive reading, the beneficial bacteria in your aquarium live on surfaces in the tank. They're not free-swimming. This is why you really can't seed a tank with water from a cycled tank. Some bacteria types can live in the water column (white cloudy water anyone?), but these aren't the nitrifying bacteria we rely on.

I will agree that bacteria live in the substrate and on all surfaces in the tank, not just the filter media. However, they're found in densest concentrations in the filter media due to the highly oxygenated water. This doesn't necessarily mean there's more bacteria in the filter, just more per cubic inch. (Another question to ponder: Are HOB filters better than canisters at housing good bacteria due to exposing the water to air?) Bacteria need oxygen to function and more available oxygen results in denser bacteria colonies.

I agree with your thought that you can start a new aquarium with enough cycled substrate and not go through a new cycle. I do wonder if the right amount of substrate would leave you any room for fish in the tank though.

 

[eco23]

Luckily I read BigJim's response before I typed one out...he perfectly summed up my thoughts.

This is a situation where a lab coat, microscope and knowing latin names isn't really necessary. Simple experience shows you the proof. I've replaced every single speck of substrate and decoration in a tank (only thing left was the actual aquarium and filter) and never saw any type of toxin spike. On the other hand, I've donated portions of filter media to friends or to set up other aquariums and experienced mini-cycles caused by removing it.

I understand that if you looked at your aquarium water under a microscope you'd see all sorts of fun little creatures swimming around, but in the general sense of "bacteria" in an aquarium we're talking about the nitrifiers...and understanding their needs of not just surface area, but an oxygen rich environment explains why and where they're mainly (not entirely) colonized.

 

[Wy Renegade]

Based on extensive reading, the beneficial bacteria in your aquarium live on surfaces in the tank. They're not free-swimming. This is why you really can't seed a tank with water from a cycled tank. Some bacteria types can live in the water column (white cloudy water anyone?), but these aren't the nitrifying bacteria we rely on.

Extensive reading of what if I may ask? I'll grant its an often stated "fact" on aquarium forums, but I have to disagree from experience. You can "seed" a tank with just water, in truth, you can establish a freshwater (and most likely a saltwater ~ although I've never done so) aquarium without any seed material whatsoever. We did it for years, long before the idea of "seeding" a tank every became popular. Set up a tank, add water, heater etc., wait a few days, then start slowly adding fish to build the bacteria levels. Now I will grant you that this process is slower than the newer favored method, and perhaps arguabley the surface area that allowed for the transfer of bacteria was the fish themselves, and yet to be on the fish, wouldn't the favorable bacteria have to be in the water also?

I will agree that bacteria live in the substrate and on all surfaces in the tank, not just the filter media. However, they're found in densest concentrations in the filter media due to the highly oxygenated water. This doesn't necessarily mean there's more bacteria in the filter, just more per cubic inch. (Another question to ponder: Are HOB filters better than canisters at housing good bacteria due to exposing the water to air?) Bacteria need oxygen to function and more available oxygen results in denser bacteria colonies.

Perhaps, and yet in a well oxygenated tank (i.e. one with enough oxygen to support a much bigger organism, say a fish), surely there is sufficient D.O. within the water column to support a thriving column of tiny bacteria?

I agree with your thought that you can start a new aquarium with enough cycled substrate and not go through a new cycle. I do wonder if the right amount of substrate would leave you any room for fish in the tank though.

Interesting question isn't it? How many bacteria does it truly take to adequately break down the waste from a single fish? Or even a multitude for that matter? Imagine just for a second, if there can be hundreds of thousands on the head of a pin, how many millions there must be in a single handful of sand from a well established aquarium.

Appreciate the discussion my friend . . . keep the thoughts coming.

 

[Wy Renegade]

Luckily I read BigJim's response before I typed one out...he perfectly summed up my thoughts.

This is a situation where a lab coat, microscope and knowing latin names isn't really necessary. Simple experience shows you the proof. I've replaced every single speck of substrate and decoration in a tank (only thing left was the actual aquarium and filter) and never saw any type of toxin spike. On the other hand, I've donated portions of filter media to friends or to set up other aquariums and experienced mini-cycles caused by removing it.

I understand that if you looked at your aquarium water under a microscope you'd see all sorts of fun little creatures swimming around, but in the general sense of "bacteria" in an aquarium we're talking about the nitrifiers...and understanding their needs of not just surface area, but an oxygen rich environment explains why and where they're mainly (not entirely) colonized.

Indeed, having a lab coat, microscope and knowing latin names isn't necessary for any part or portion of aquarium keeping, unless you desire to do so .

Certainly an excellent bit of proof. Indeed we know that a truly "cycled" tank simply means that the tank contains sufficient bacteria populations to adequately break down the waste produced in the aquarium to a level sufficient to prevent the build-up of toxins (in the form of ammonia and nitrites) to harmful levels ~ agreed? If we remove a large enough portion of that sustaining population of bacteria, we experience a minicycle in what was a previously balanced aquarium until bacteria populations build up to sufficient levels correct? Hence the challenge of the statement.

Can you perhaps describe for us the method by which you were able to remove all the substrate from a functioning aquarium without causing a mini cycle or cycle? Its been my own experience that completely disrupting the substrate bed within an aquarium almost always causes at the very least a minicycle. In fact sometimes something as simple as simply vaccuming the substrate can cause a minicycle.

I find the oxygen argument to be an interesting one as well. Let us consider a saltwater tank for a moment if we might. Same nitrifying bacteria are present? And yet the nitrifying bacteria within the saltwater tank exist in sufficient numbers to process tank waste without the benefit of an oxygenating HOB filter. Which in a sense brings us around to the question Jim proposed on HOB vs. canister. Certainly canisters are effective at filtering and obviously sustain very high levels of nitrifying bacteria without that exposure to highly oxygenated water. So do nitrifying bacteria truly requiring higher levels of oxygen? given their presence within soil (nitrifying bacteria found in the soil are the same as the nitrifying bacteria that are found in our aquariums), I have to wonder at the accuracy of that thought as well.

Good thoughts and good questions, keep em coming folks!

 

[slitherbomb]

So far I've had 3 saltwater tanks(14g biocube, 40g, 75g) all of which have been filled with natural saltwater from my backyard and I've not experienced any spikes in parameters after adding fish. I've never cycled. I used the API test kits that everyone here uses to check too. For the first 2 weeks or so, I checked daily because everyone told me that it couldn't be true(everyone on here at least, not in real life) but no spike ever came. There are definitely nitrifying bacteria in the water column.

 

[eco23]

Indeed, having a lab coat, microscope and knowing latin names isn't necessary for any part or portion of aquarium keeping, unless you desire to do so .

Certainly an excellent bit of proof. Indeed we know that a truly "cycled" tank simply means that the tank contains sufficient bacteria populations to adequately break down the waste produced in the aquarium to a level sufficient to prevent the build-up of toxins (in the form of ammonia and nitrites) to harmful levels ~ agreed? If we remove a large enough portion of that sustaining population of bacteria, we experience a minicycle in what was a previously balanced aquarium until bacteria populations build up to sufficient levels correct? Hence the challenge of the statement.

Can you perhaps describe for us the method by which you were able to remove all the substrate from a functioning aquarium without causing a mini cycle or cycle? Its been my own experience that completely disrupting the substrate bed within an aquarium almost always causes at the very least a minicycle. In fact sometimes something as simple as simply vaccuming the substrate can cause a minicycle.

I find the oxygen argument to be an interesting one as well. Let us consider a saltwater tank for a moment if we might. Same nitrifying bacteria are present? And yet the nitrifying bacteria within the saltwater tank exist in sufficient numbers to process tank waste without the benefit of an oxygenating HOB filter. Which in a sense brings us around to the question Jim proposed on HOB vs. canister. Certainly canisters are effective at filtering and obviously sustain very high levels of nitrifying bacteria without that exposure to highly oxygenated water. So do nitrifying bacteria truly requiring higher levels of oxygen? given their presence within soil (nitrifying bacteria found in the soil are the same as the nitrifying bacteria that are found in our aquariums), I have to wonder at the accuracy of that thought as well.

Good thoughts and good questions, keep em coming folks!

First, my understanding of Saltwater aquaria is extremely limited, so much of the relations to FW are simply accounts I've read from others. It's my understanding that SW contains different strains of beneficial bacteria compared to FW (hence one of my concerns with products like Stability which are an all in one product for any type of tank). I've also heard information that inhibiting bio-filter development in filter media is a common practice...such as regularly cleaning mechanical filtration in tap water (again, second hand info there).

The method I used for removing substrate involved a dust pan and my hands. I pulled out all decor, scooped out the substrate, replaced it with sand and new decor. I monitored the parameters for over a week with an API Master Kit and never recorded even a hint of a toxin spike. I've done this in several aquariums with the same outcome.

Perhaps information like gravel cleaning causing mini-cycles is extremely overrated. Honestly, I've never heard of a single account of toxin spikes caused by gravel vacuuming. The longer I'm involved in the hobby, the more I realize the balance isn't quite as sensitive as many people believe, except for situations like a tank in the cycling process or immediatly after.

Another interesting piece of information I've read in articles is that beneficial bacteria does not actively seek out ammonia / nitrite...it basically has to be brought to them. This may be another cause of why filter media is a popular location for them to colonize since the water is always circulating through, as opposed to other areas of the tank which are not as efficiently turned over.

As for oxygenation, I think you'd have a hard time finding disagreement that the filter is more oxygenated compared to substrate due to agitation of the water moving through the media, perhaps as well as other reasons I'm not familiar with. There are minimum requirements for dissolved o2 just like nitrifying bacteria have requirements for a minimum amount of other nutrients and alkalinity. Perhaps it's a fair comparison that I could choose to live in a desert with limited resources, but naturally I will seek out the most naturally abundent location to call my home.

 

[eco23]

So far I've had 3 saltwater tanks(14g biocube, 40g, 75g) all of which have been filled with natural saltwater from my backyard and I've not experienced any spikes in parameters after adding fish. I've never cycled. I used the API test kits that everyone here uses to check too. For the first 2 weeks or so, I checked daily because everyone told me that it couldn't be true(everyone on here at least, not in real life) but no spike ever came. There are definitely nitrifying bacteria in the water column.

If that is true (which honestly I have my concerns with), it should be indisputable evidence that there are significant differences between FW and SW nitrifying bacteria...or at the very least their behavior in home aquaria compared to other environments. Obviously in FW, filling a tank with water from an established tank and stocking it is a recipe for disaster. Now there are situations where taking a piece of filter media and squeezing it out into water to donate into a new tank can help introduce beneficial bacteria into a tank, however it is in no way an "insta-cycle" as people refer to certain ways to transplant bacteria.

I've used this following example several times before on the site...but it is true based on my experience, both first hand as well as all the members I communicate with daily on the site-

Substrate, decorations, filter squeezings, etc...are a true way to "seed" a tank. It introduces some degree of beneficial bacteria into a tank and lets it begin colonizing...basically planting a seed in order for it to grow.

Now, donating filter media is like planting a fully grown tree instead of it's seedlings. It instantly brings over a significant amount of beneficial bacteria which should immediately be capable of handling a larger amount of toxins compared to any other type of item. Again, this is not speculation, this is experience.

As previously stated, a tank being considered "cycled" simply refers to the proportion of beneficial bacteria : toxins produced in a tank. I really do believe that simple experience trumps the need to study at length (although I've probably read every article on Google about nitrifying bacteria) in terms of the amount of beneficial bacteria found in filter media vs substrate or other items.

 

[slitherbomb]

If that is true (which honestly I have my concerns with), it should be indisputable evidence that there are significant differences between FW and SW nitrifying bacteria...or at the very least their behavior in home aquaria compared to other environments. Obviously in FW, filling a tank with water from an established tank and stocking it is a recipe for disaster. Now there are situations where taking a piece of filter media and squeezing it out into water to donate into a new tank can help introduce beneficial bacteria into a tank, however it is in no way an "insta-cycle" as people refer to certain ways to transplant bacteria.

I've used this following example several times before on the site...but it is true based on my experience, both first hand as well as all the members I communicate with daily on the site-

Substrate, decorations, filter squeezings, etc...are a true way to "seed" a tank. It introduces some degree of beneficial bacteria into a tank and lets it begin colonizing...basically planting a seed in order for it to grow.

Now, donating filter media is like planting a fully grown tree instead of it's seedlings. It instantly brings over a significant amount of beneficial bacteria which should immediately be capable of handling a larger amount of toxins compared to any other type of item. Again, this is not speculation, this is experience.

As previously stated, a tank being considered "cycled" simply refers to the proportion of beneficial bacteria : toxins produced in a tank. I really do believe that simple experience trumps the need to study at length (although I've probably read every article on Google about nitrifying bacteria) in terms of the amount of beneficial bacteria found in filter media vs substrate or other items.

Or maybe there just might be a difference between finding a natural sources of water vs water from someone else's aquarium. This has just been my experience, and when the guy at Petco who had saltwater aquariums told me about this, I had my doubts, but now I have found it to be true, or at least true for me.

 

[adeebm]

I find the oxygen argument to be an interesting one as well. Let us consider a saltwater tank for a moment if we might. Same nitrifying bacteria are present? And yet the nitrifying bacteria within the saltwater tank exist in sufficient numbers to process tank waste without the benefit of an oxygenating HOB filter. Which in a sense brings us around to the question Jim proposed on HOB vs. canister. Certainly canisters are effective at filtering and obviously sustain very high levels of nitrifying bacteria without that exposure to highly oxygenated water. So do nitrifying bacteria truly requiring higher levels of oxygen? given their presence within soil (nitrifying bacteria found in the soil are the same as the nitrifying bacteria that are found in our aquariums), I have to wonder at the accuracy of that thought as well.

Good thoughts and good questions, keep em coming folks!

Oxygenation is one factor in the number of bacteria that can be supported over a surface area. Flow is another thing to consider. Nitrifying bacteria need oxygen, being aerobic, and also need a food source (ammonia/nitrite). It stands to reason then, that an HOB, which oxygenates the water and supplies them with a constant source of ammonia, due to the high flow rate of water passing through it, will be able to support a higher density of bacteria then say gravel substrate. Gravel has little flow though it, thus oxygen and ammonia availability become limiting factors. Now, add flow to the gravel and you get a UGF, a common type of filter, and basically the same function as an HOB.

Canisters are also efficient for bacterial growth because of water flow, but provide less oxygen. Still, since the water itself is oxygenated and the available oxygen in the canister is replenished as water flows, I don't think the difference between an HOB and a canister is significant. A volume of water will contain a certain level of dissolved oxygen. As the bacteria use up this oxygen, it needs to be replenished. This can either be done by direct exposure to air, as in an HOB, or simply by pulling new water through. Gas exchange at the surface will keep oveall oxygen levels at an equilibrium.

Why do saltwater tanks contain adequate bacteria levels without an HOB? Water flow. Live rock serves as a porous material with large surface area for bacteria to colonize. Again, these bacteria need oxygen and ammonia, which is one reason why saltwater tanks with liverock have high water movement, more than you usually find in FW. The liverock serves the same purpose as ceramic media in an HOB. If you wanted, you could get dry liverock and some powerheads, and use the same concept in an FW tank, without needing an HOB.

--Adeeb

 

[aqua_chem]

Two points here that I want to weigh in on briefly. I'll come back and hit more points when I get home from work.

So, if I take my aquaclear filter and I compare the available surface area within the media within it, how does that compare to the available surface area in my substrate? Even if I'm willing to concede that the ceramic media and the sponges are significantly more porous than the substrate in question and I limit myself to the top inch or so of substrate within the tank, by hammering the ceramic media into powder and cutting the sponge down into 1/4" strips, I'm still forced to concede that there is significantly more viable surface area within the substrate then there is within my filter.

I disagree with this. You're thinking to much about volume and not enough abut surface area. I looked up the surface area of the ceramic "Ehfisubstrat" that came with my canister filter, and it is marketed at about 20,000 square feet per gallon. I have about 3L in my filter (more than the 2L that it comes with). So, after some quick math, my little 2217 has just under half an acre of surface area. All/most of that surface area is readily supplied with nutrients and oxygen by the flow of the filter, meaning that the bacteria colonies can be larger and more robust. Compare that to the substrate where only the top inch or so is really supplied with nutrients. Low layers would still have aerobic bacteria, but they won't be thriving like the upper ones would be, and even those bugs envy the life of filter-bacteria.

I really don't think that the water in filters is especially oxygenated. Maybe some filters (biowheels), but it seems like most of mine only have water/air contact right before the water leaves the filter. My AC is certainly this way.


The second thing is something that has intrigued me for a long time, and that is the role of phytoplankton in our ecosystems. They are present in both salt and freshwater, and they have to be getting their nitrogen from somewhere. So while I due doubt that bacteria has a major presence in the water, I would imagine that there could be a whole host of other organism, autotrophic or otherwise, floating around that could also make use of nitrogenous byproducts. I find it hard to believe that there is only one organism that can make use of a single, readily available resource like reduced nitrogen. We see this in plants as well.

Some bacteria types can live in the water column (white cloudy water anyone?), but these aren't the nitrifying bacteria we rely on.

For anyone that is interested, the cloudy water we see is from (if I recall correctly) heterotrophic bactceria. Our nitrifying bacteria are chemotrophs.

Set up a tank, add water, heater etc., wait a few days, then start slowly adding fish to build the bacteria levels. Now I will grant you that this process is slower than the newer favored method, and perhaps arguabley the surface area that allowed for the transfer of bacteria was the fish themselves, and yet to be on the fish, wouldn't the favorable bacteria have to be in the water also?

I don't think anyone is arguing that there is no bacteria in the water column. It's just that there is a ton more attached to surfaces. Think about your garbage can. You can sanitize a trash can and put sanitized food in it, and if left unsealed out in the open, it will begin to mold, rot, and whatnot. Thats because all of those fungi and bacteria and god only knows what else are everywhere. They're even in the air you breath. In fact, I bet you just sucked some in just now! But compared to on the surface of about anything, there's a trifling amount. But you certainly wouldn't eat a decomposing sandwich.


An additional concern: It is entirely possible that bacteria will not multiply properly (or quickly) without an attached surface. Much of the bacteria in water will come from established colonies on a surface somewhere. The bacteria breaks off and floats along until it finds another surface. Many bacteria (not sure about out nitrifying bacteria) have life cycles like this.

 

[Wy Renegade]

First, my understanding of Saltwater aquaria is extremely limited, so much of the relations to FW are simply accounts I've read from others. It's my understanding that SW contains different strains of beneficial bacteria compared to FW (hence one of my concerns with products like Stability which are an all in one product for any type of tank). I've also heard information that inhibiting bio-filter development in filter media is a common practice...such as regularly cleaning mechanical filtration in tap water (again, second hand info there).

Fair enough, although the existence of success of products like stable (at least by some accounts) would appear to argue in favor of the fact that the bacteria as the same. Not sure what you are referencing with the inhibition of bio-filter statement?

The method I used for removing substrate involved a dust pan and my hands. I pulled out all decor, scooped out the substrate, replaced it with sand and new decor. I monitored the parameters for over a week with an API Master Kit and never recorded even a hint of a toxin spike. I've done this in several aquariums with the same outcome.

Interesting, I can't image that you were able to accomplish that without stirring up boat loads of suspended sediments and releasing trapped debris which should certainly have kicked off at least a minicycle. Personally, I've never even been able to wash sand or gravel out even in a bucket without turning the water a nasty brown from suspended substrate and debris. Perhaps these were relatively new tanks?

Perhaps information like gravel cleaning causing mini-cycles is extremely overrated. Honestly, I've never heard of a single account of toxin spikes caused by gravel vacuuming. The longer I'm involved in the hobby, the more I realize the balance isn't quite as sensitive as many people believe, except for situations like a tank in the cycling process or immediatly after.

Overrated by whom? I participated in at least one thread on this very site just this week on this particular issue. A yet the balance is disrupted in your established tanks by the sharing of a small amount of the established filter media?

Personally, I do agree with you that the balance isn't nearly as sensitive as many people believe, I think that probably has a lot to do with the reproductive capability of the baterium themselves, as well as a signicant abundance of space they are able to occupy within the aquarium.

Another interesting piece of information I've read in articles is that beneficial bacteria does not actively seek out ammonia / nitrite...it basically has to be brought to them. This may be another cause of why filter media is a popular location for them to colonize since the water is always circulating through, as opposed to other areas of the tank which are not as efficiently turned over.

Indeed the part about then not actively seeking it out is quite true. And yet I must question the assumption that the filter somehow receives more flow. Isn't true that the filter is presumidly turning over the entire water volume of the aquarium? Often times in the space of only hours or even an hour? If this is true, then all the water within the aquarium would not only be exposed to the surface of the filter media, but also to the surface of the substrate. If this were not the case then within the aquarium one would have to expect to find areas of water significantly higher is dissolved nutrients as they failed to be filtered the same as other areas, and as a result we would have to expect to see differeing results from ammonia, nitrite, and nitrate tests taken on water from different areas of the aquarium. True? Personally, I've never found that to be my experience. So I must conclude that all water within the little glass box is moving in a very similar fashion and therefore both substrate and filter get the same exposure to oxygen rich water and to nutrients.

As for oxygenation, I think you'd have a hard time finding disagreement that the filter is more oxygenated compared to substrate due to agitation of the water moving through the media, perhaps as well as other reasons I'm not familiar with. There are minimum requirements for dissolved o2 just like nitrifying bacteria have requirements for a minimum amount of other nutrients and alkalinity. Perhaps it's a fair comparison that I could choose to live in a desert with limited resources, but naturally I will seek out the most naturally abundent location to call my home.

Indeed there are, and in fact that was my I limited the discussion to the top portion of the substrate. If we go beyond a certain depth, we enter into a area that is potentially anaerobic, and the discussion becomes invalid. While I will concede that indeed the water immediately within the HOB filter has a higher oxygen supply, I would argue that it is in fact signicantly higher than other areas of the aquarium (again, assume that we are talking about an aquarium that has an adequate ammount of flow). If there were not sufficient levels of oxygen to support the bacteria populations, then there certainly would not be sufficient levels of oxygen to support the fish at the bottom of the aquarium. In fact the purpose of using a filter that turns over an aquarium X number of times per day is in order to insure the equatible distribution of substances such as dissolved oxygen and nutrients throughout the entire tank, as well to ensure that all water in the tank travels across the filter and has an opportunity to have said nutrients removed is it not?

 

[Wy Renegade]

If that is true (which honestly I have my concerns with), it should be indisputable evidence that there are significant differences between FW and SW nitrifying bacteria...or at the very least their behavior in home aquaria compared to other environments. Obviously in FW, filling a tank with water from an established tank and stocking it is a recipe for disaster. Now there are situations where taking a piece of filter media and squeezing it out into water to donate into a new tank can help introduce beneficial bacteria into a tank, however it is in no way an "insta-cycle" as people refer to certain ways to transplant bacteria.

Wait, wait my friend. If we are going to allow personal experiences as proof in this thread (which I certainly agree that we must for the sake of our discussion, and that certainly is the point from which you are presenting your evidence), then we must give all personal experiences the same weight and the same respect. It is not fair of you to dispute someone else's experiences when asking others to accept your experiences as proof positive. You also ignored my earlier statement in which I stated I've seeded freshwater tanks with water (actually many times). Does that mean that these tanks were fully cycled and ready to fullly stock? Not at all, but the "seed" populations were there and the bacteria populations were able to begin growing from there.

I do agree that I would like to see more information however on how the individual here "stocked" their tanks. But if the stocking was slowly, then I would have to argue in favor thereof.

I've used this following example several times before on the site...but it is true based on my experience, both first hand as well as all the members I communicate with daily on the site-

Substrate, decorations, filter squeezings, etc...are a true way to "seed" a tank. It introduces some degree of beneficial bacteria into a tank and lets it begin colonizing...basically planting a seed in order for it to grow.

Now, donating filter media is like planting a fully grown tree instead of it's seedlings. It instantly brings over a significant amount of beneficial bacteria which should immediately be capable of handling a larger amount of toxins compared to any other type of item. Again, this is not speculation, this is experience.

As previously stated, a tank being considered "cycled" simply refers to the proportion of beneficial bacteria : toxins produced in a tank. I really do believe that simple experience trumps the need to study at length (although I've probably read every article on Google about nitrifying bacteria) in terms of the amount of beneficial bacteria found in filter media vs substrate or other items.

So you are saying that donating filter media to a newly established tank allows for the full stocking of said newly established tank? I hardly think so, unless you are donating the entire filter. Certainly discussion here as well as on other forums, as well as personal experience will not bear that out. As far as "seed" material, I agree. But how much seed material are we talking when someone talks about moving substrate? or decorations, or even water. Has anyone ever donated half the sand substrate out of their aquarium to a newly established tank?

 

[stingrays4]

Hi a very interesting thread this. Now before i start i am certainly no expert and certainly hardly ever use test kits. All assumptions are based on many many years of experience.
First off, bacteria do live almost every where inside the aquarium,hence why i never advocate over cleaning the decor if at all! The bacteria thrives more in the filter simply because the surface provided by the sponge,sintered glass media is more to there liking,with a constant supply of both oxygenated water and food for the bacteria? As for seeding another tank with water or substrate from a mature tank will help but as already said will not provide an instant cycled tank. A lesson i learnt not long ago was very interesting and only thanks to a more knowledgeable fish keeper helped more sort it out! I dissmantled a six foot tank and placed some of the fish into a four foot set up with the filter,wood substrate decor etc,so my theory being the tank would be instantly cycled,so proceeded and all went well,but the tank took nearly six months to settle? The problem was that although the filter was mature as was the water,decor etc,because the tank was now smaller with a lighter bio load the bacteria had to readjust hence the tank remaining looking 'murky' until the bacteria had readjusted? Also Simon me mate up the local fish shop also agreed with me in that the bacteria levels in an aquarium are only as numerous as the amount of food {fish waste} available to them,so when we place new fish into the aquarium they have to multiply to compensate,which may only take a day or two,hence why we should never put to many fish into a tank and leave it at least a fortnight between getting new fish?
External filters are very good but trickle filters where the water is more exposed to the air will be more efficient in my opinion.
Also the idea that most of the bacteria is in the substrate is why we used to use undergravel filter plates,but as they blocked they became very inefficient,as they are much harder to clean than standard filters such as externals and internals.
Footnote how do they measure or come up with what is supposed to be the surface area of sintered glass media such as eheims ehfisubstrate?

 

[Wy Renegade]

Or maybe there just might be a difference between finding a natural sources of water vs water from someone else's aquarium. This has just been my experience, and when the guy at Petco who had saltwater aquariums told me about this, I had my doubts, but now I have found it to be true, or at least true for me.

While I personally agree with you on the existence of such bacteria within the water column, I have to say that I do not think that they are found within the water column in signicant enough ammounts to allow for the full establishment of a entire aquarium just based on water. Can you please give us more information on the stocking levels and methods you employed?

 

[aqua_chem]

Footnote how do they measure or come up with what is supposed to be the surface area of sintered glass media such as eheims ehfisubstrate?

Probably Langmuir Isotherm adsorption experiments.

 

[Wy Renegade]

Oxygenation is one factor in the number of bacteria that can be supported over a surface area. Flow is another thing to consider. Nitrifying bacteria need oxygen, being aerobic, and also need a food source (ammonia/nitrite). It stands to reason then, that an HOB, which oxygenates the water and supplies them with a constant source of ammonia, due to the high flow rate of water passing through it, will be able to support a higher density of bacteria then say gravel substrate. Gravel has little flow though it, thus oxygen and ammonia availability become limiting factors. Now, add flow to the gravel and you get a UGF, a common type of filter, and basically the same function as an HOB.

Canisters are also efficient for bacterial growth because of water flow, but provide less oxygen. Still, since the water itself is oxygenated and the available oxygen in the canister is replenished as water flows, I don't think the difference between an HOB and a canister is significant. A volume of water will contain a certain level of dissolved oxygen. As the bacteria use up this oxygen, it needs to be replenished. This can either be done by direct exposure to air, as in an HOB, or simply by pulling new water through. Gas exchange at the surface will keep oveall oxygen levels at an equilibrium.

I would point out first of all that regardless of available oxygen and food, bacterial colonization would still be limited by the availability of space. Additionally, I would point you back to my earlier responses (posted after you posted your comments) in regardes to equitable distribution of oxygen throughout the aquarium provided adequate flow.

If indeed one can argue for the fact that water flow through a cansister filter can provide adequate oxygen levels for bacteria, cannot the same argument be applied to the water flow through the gravel? Water does not circulate independently through different areas of the aquarium (for the most part). Rather circulation is generated by the filters and is generally fairly evenly distributed throughout the aquarium (excepting flow deprived areas such as deep within the substrate or deep within the rock).

Why do saltwater tanks contain adequate bacteria levels without an HOB? Water flow. Live rock serves as a porous material with large surface area for bacteria to colonize. Again, these bacteria need oxygen and ammonia, which is one reason why saltwater tanks with liverock have high water movement, more than you usually find in FW. The liverock serves the same purpose as ceramic media in an HOB. If you wanted, you could get dry liverock and some powerheads, and use the same concept in an FW tank, without needing an HOB.

--Adeeb

Ah, and now we begin to get at the crux - thank you my friend. Isn't it also true that the same denitrifying bacteria are found within the LS base of the saltwater aquarium as are found within the LR surface area? In fact the original tanks running deep sandbed were successfully run without any LR at all were they not? Now keep in mind that flow in and of itself does not necessarily provide for oxygenation, surface aggitation is also required so that oxygen can enter the water in the first place. But again I ask the question, does the HOB filter truly move the water across it independent of the rest of the water within the aquarium or does it not move all the water within the aquarium to that rate of flow?

 

[eco23]

Fair enough, although the existence of success of products like stable (at least by some accounts) would appear to argue in favor of the fact that the bacteria as the same. Not sure what you are referencing with the inhibition of bio-filter statement?

Based off information I've found, certain types of beneficial bacteria colonize in a salinity range of 0-6ppt, while a slightly different species accept ranges of 6-44ppt. Since we know the ocean is an average of 35ppt...that seems like very credible information that there is a difference between the types of bacteria found in different environments. (My PC crashed and I lost the dozens of bookmarks I had...but with a bit of searching I'm sure you can find the same references.)

Interesting, I can't image that you were able to accomplish that without stirring up boat loads of suspended sediments and releasing trapped debris which should certainly have kicked off at least a minicycle. Personally, I've never even been able to wash sand or gravel out even in a bucket without turning the water a nasty brown from suspended substrate and debris. Perhaps these were relatively new tanks?

Not sure what to tell you there. It happened in 3 of my tanks. Gravel came out, sand went in, a couple pwc's to help clear the water, debris settled by the next day and there were no toxin spikes. I've done this in 3 tanks and had the same results. You'll commonly find on the threads here the advice for people switching substrates that "You should monitor for mini-cycles, but I never had a problem." I've seen that statement many times by many different members on this site.

Overrated by whom? I participated in at least one thread on this very site just this week on this particular issue. A yet the balance is disrupted in your established tanks by the sharing of a small amount of the established filter media?

You're telling me that someone vacuumed their gravel and had a mini-cycle? Either I missed that thread or one of us may have not had all the info. I'd be willing to bet that there was another variable there like switching filter media. And yes, removing significant amounts (perhaps 30%) of bio-media has caused mini-cycles. A few days and a few pwc's easily handled it...but it's happened.

Indeed the part about then not actively seeking it out is quite true. And yet I must question the assumption that the filter somehow receives more flow. Isn't true that the filter is presumidly turning over the entire water volume of the aquarium? Often times in the space of only hours or even an hour? If this is true, then all the water within the aquarium would not only be exposed to the surface of the filter media, but also to the surface of the substrate. If this were not the case then within the aquarium one would have to expect to find areas of water significantly higher is dissolved nutrients as they failed to be filtered the same as other areas, and as a result we would have to expect to see differeing results from ammonia, nitrite, and nitrate tests taken on water from different areas of the aquarium. True? Personally, I've never found that to be my experience. So I must conclude that all water within the little glass box is moving in a very similar fashion and therefore both substrate and filter get the same exposure to oxygen rich water and to nutrients.

Perhaps this varies based on filtration. In fact it is recommended by several resources to take water samples from different levels of the aquarium.

Indeed there are, and in fact that was my I limited the discussion to the top portion of the substrate. If we go beyond a certain depth, we enter into a area that is potentially anaerobic, and the discussion becomes invalid. While I will concede that indeed the water immediately within the HOB filter has a higher oxygen supply, I would argue that it is in fact signicantly higher than other areas of the aquarium (again, assume that we are talking about an aquarium that has an adequate ammount of flow). If there were not sufficient levels of oxygen to support the bacteria populations, then there certainly would not be sufficient levels of oxygen to support the fish at the bottom of the aquarium. In fact the purpose of using a filter that turns over an aquarium X number of times per day is in order to insure the equatible distribution of substances such as dissolved oxygen and nutrients throughout the entire tank, as well to ensure that all water in the tank travels across the filter and has an opportunity to have said nutrients removed is it not?

Obviously I don't have a way to measure dissolved o2 at different levels of an aquarium...but yes, I believe the filter area / surface has more oxygen content. This is why fish gather at the surface when they are having respiratory issues.