Bioballs outcompeteing LR?

[MikeS]

Hi all...

Got into an interesting discussion with Clayton about bioballs outcompeteing LR for aerobic nitrification and I'd like to go deeper into this and see what specifics we can come up with here. Personally, I question the level at which this takes place, but others disagree...

Just keep in mind that live rock doesn't do any good for biological filtration as long a wet/dry is installed. Any ammonia and nitrites in the water will be quickly removed by the bio-balls first, leaving nothing for the rock. This creates a situation where you have no nitrifying bacteria on or in the rock.

Boomer, who's input we all respect, sees it similarly...a quote of his from a separate thread...

Originally Posted by Boomer

It is not that bioballs are bad, if you know what you are doing. We used them for 2 decades and you DO NOT always get high nitrates. They are more of a pain in the A_ss. The real reason is that they compete with nitrifying bacteria, which reduces the population density of nitrifying bacteria in the SB or LR. It is here where the Nitrate can be fed right to Facultative Anaerobic Bacteria, which convert it to N2 gas. Nitrification----->Denitrification is best achieved by proximity (bacteria right next to each other, which is not the case with bioballs.)

I'm having a hard time accepting that this is actually happening to a significant degree, somebody needs to steer me straight....

Ok...in order to all get on the same page, I'm going to pick up where I left off in my discussion with Clayton in the other thread....

http://www.reeffrontiers.com/forums/showthread.php?t=9443

I understand what you're getting at, but I think many of your assumptions are incorrect. I'll explain below.

don't confuse a zero test result with its absence in the system....

Toxic ammonia and nitrites are eliminated, that's the entire purpose of biological filters. Whether they're in a different state or not is moot. I'm not even sure what this has to do with our discussion.

Ok...these are not "eliminated". They are being produced constantly in the tank and are constantly being processed into different compounds. If they were absent, the process would shut down. Its important to the discussion because they have a lot to do with bacterial populations in the tank to start with.

The reason trickle filters will always outwork live rock is because the bacteria on the bio-balls DO come into contact with more nitrogen than the bacteria on the live rock.

Nitrogen is the end of the reduction cycle, not the beginning.

Not true, at a basic level nitrogen is the entire cycle. Ammonia, nitrites and nitrates are all nitrogen-based molecules. That's why it's referred to as the "nitrogen cycle".

Ok...agreed that Nitrogen is a component of the entire cycle from beginning to end., I may have misspoke myself here. It's called the nitrogen cycle because it tracks the path of nitrogen through the bacterial transformation of compounds in the tank. The point I was trying to make, while the recycling of Nitrogen is present at every step in the process, it in and of itself Nitrogen is not a fuel for bacterial growth, it is simply a critical ingredient for the metabolic process of the bacteria. An absolutely essential ingredient, yes, but not the limiter here...

for example, in reduction of ammonia/ammonium, the bacteria strip the ammonium molecule (NH4) of hydrogen and affix it with oxygen, and expel it as nitrite (NO2). The nitrogen itself is not used up, it is simply an inert "carrier" that aids in the metabolic process and is then expelled back into the system. So, the amount of nitrogen the bacteria on the bioballs comes in contact with has absolutely nothing to do with their populations. If I'm wrong here, somebody please correct me.

The surface of LR is an ideal place for bacterial growth...lots of surface area, lots of nutrients, exposure to oxygen rich water

The very surface of the rock where water flow is great not only is quite small, but it's also unsuitable for high numbers of bacteria due to the high flow rate of water. Higher numbers grow inside the rock, not in the water column.

Now here is where I fail to see the logic. How exactly does water flow have a significantly negative effect on bacterial growth? I'll use a standard hang on power filter as an example here, the type with the fabric pads in them. These pads are exposed to a very high rate of direct water flow versus surface area, yet large amounts of bacteria thrive in them, giving them the reputation as a "nitrate factory" as well. Flow obvioulsy does not hinder bacterial growth in these areas, how would it do so on LR?

Even if we do assume this is the case on the top surface of the rock, that does not mean the rock as a whole is not a favorable environment for aerobic bacterial activity. LR is typically very porous...slightly deeper in the rock you will have plenty of surface area that is not subjected to nearly the velocity of flow as the surface, yet still has plenty of nutrient rich, oxygenated water being carried into it. The zones in the rock don't go abruptly from aerobic to anaerobic, there is an oxygen reduction as you deeper, creating an increasingly anoxic zone between the two. The depths at which these occur in the rock are a basic function of rock porosity and water flow.

I agree with what you are saying here, however, I thought the issue we were dealing with was nitrate production, not reduction.

In order to tackle reduction you have to look at production. In this case it's extremely important.

Ok I see where you are going with this...the rate of nitrate production versus the rate of nitrate reduction is critical to your argument...

continued on next post due to 10000 character limit per thread...

MikeS

 

[MikeS]

Wet/Dry filters with bioballs simply provide additional surface area for additional aerobic reduction to take place, which leads to a more rapid production of nitrate.

Again, speed isn't the only factor. If you have a wet/dry on your system it absolutely will become the dominant part of the biological process. When it converts ammonia and nitrites at the efficiency it will, it leaves nothing for the rock. If there's nothing inside the rock eliminating those, you'll get none eliminating nitrates. Speed has little to do with it; it's more a matter of location.

I'll agree, speed isn't the only factor, but I feel it is a major contributor to what we are seeing here. Yes, the wet/dry filter likely provides the most favorable environment in the tank for rapid growth of bacteria. But to suggest that it will leave nothing for the rock, you have to work on several pretty broad assumptions.

First, one would have to assume that the great majority of waste is ending up in the bioball chamber. I don't see how this is possible, lots of detritus and waste accumulate on the rock, bottom of the tank, ect. Bacterial activity is taking place on the waste itself, in the water column, on the rock, basically all the surfaces of the tank. The bioball chamber is getting what solid waste and saturated nutrients are in the water column and are sucked into the feed pump or overflow, this is by no means the majority of nutrients in the system.

Second, one has to assume that the conditions in the bioball chamber versus the surface area of the bioballs are that much more favorable as to create a situation where aerobic bacterial activity will cease in other parts of the tank. Granted, the highly oxygenated environment of the bioball chamber creates a superior physical environment for these types of bacteria, but the live rock in a typically stocked reef tank has much greater total area for aerobic activity (whether it be on or slightly in the rock) than the average group of bioballs, not to mention the fact that the bacteria on the LR generally has the first crack at the waste and nutrients in the system, as much of it accumulates or is produced on or near the rock...

You'll get the exact same effect if you remove the bioballs and replace them with LR in the wet/dry, all you have done is change the media on which the bacteria grows

Again, not completely true. Bio-balls aren't porous enough to grow anaerobic bacteria, rocks are. If the rocks are submerged they will remove nitrates as well as ammonia and nitrites; provided of course you don't have bio-balls in the chamber above.

I'm sticking by this one...a quote from mojo from a separate thread...

Originally Posted by mojoreef
It wouldnt even have to be bioballs in thier to create the nitrate problem. The concept is that th highly oxygenated water passing over the multi-surfaced bioball allows for the creation of nitrifing bacteria (as mentioned above) this type of system works well for a FO system as fish can handle Nitrates. Corals on the other hand cannot. It wouldnt matter what you put in thier in its place it would have the same effect as the same enviroment is being created (highly airated water over a surface) bioballs are just used becuase they have so much exposed surface area..
Dont worry about nitrifing bacteria in your tank, thiers plenty. They cover every surface of your tank, if you go BB or not you will have enough. Having to rince them is to much work IMHO. I would just leave the area open and use it for equipment.

You are simply substituting one form of surface area for another...as stated it all boils down to highly oxygenated water flowing over a surface area for bacterial growth, it doesn't matter if it is rock, plastic, fabric, ect, the end result is the same. Granted, you are getting a degree nitrate reduction in the depths of the rock, but I'll get to that next....

The bottom line is that wet/dry filters will end up creating nitrates that must be removed in water changes; while live rock only will not. This is not a huge debate; it's a widely recognized fact

To state that live rock only as a source for biological reduction won't produce nitrates simply is not true. Live rock does reduce nitrates, but not at the same rate the aerobic bacterial activity produces them. The process of bacterial nitrate reduction is a much slower one than bacterial nitrate production. This is an observable condition. For example, I have 100lbs of live rock curing in two separate tanks in my basement right now, they have been there for around a month. These rocks are curing in bare bottom tanks, no wet/dry, no hang on power filters, no additional area other than the live rock for bacteria to grow, only a few powerheads in each tank providing flow. Just prior to posting this, I went and tested the water in both tanks. Both had 0 ammonia, 0 nitrite....as for Nitrate, one tank had 20ppm, the other had 25ppm. This demonstrates exactly what I was saying, nitrate reduction in LR does not occur at the same rate as nitrate production in the system. If it did, I'd see zero nitrates....

whew....long post.... :lol: sorry, I tend to get a bit carried away at times...

I'm always willing to go part way on this and entertain all theories....I can definitely see how a wet/dry system would have the potential to skew bacterial populations from other areas of the tank given certain circumstances, but I still feel that their reputation as a nitrate factory is due more to the increased rate at which existing nutrients in the tank are converted into nitrate due to a highly aerobic environment combined with more surface area for larger bacterial populations than a reduction in activity in the LR...

for those of you who have made it this far, thanks for reading and I'm looking forward to your input...

MikeS

 

[clayswim]

somebody needs to steer me straight....

I'm trying

Ok...these are not "eliminated".

They are for practical purposes; which is to say they're at levels harmless to our pets. The reason the bacteria stay alive is because there's always more ammonia entering the water. It's not as though they die immediately when there's no more ammonia. If that were the case we'd all be in trouble during power outages.

So, the amount of nitrogen the bacteria on the bioballs comes in contact with has absolutely nothing to do with their populations.

It does when those same bacteria consume part of the molecule the nitrogen is attached to.

How exactly does water flow have a significantly negative effect on bacterial growth?

Because rock is harder to attach to than fabric. It's the same reason that hermit crabs fall off of our rocks all the time but never fall from filter floss. It's "sticky", therefore easier to hang onto. Bacteria does blow off of rocks that receive strong currents; in the same way we reduce some bacteria population by vacuuming sand with a powerful suction.

slightly deeper in the rock you will have plenty of surface area that is not subjected to nearly the velocity of flow as the surface, yet still has plenty of nutrient rich, oxygenated water being carried into it. The zones in the rock don't go abruptly from aerobic to anaerobic, there is an oxygen reduction as you deeper, creating an increasingly anoxic zone between the two.

Agreed on both accounts, but they still don't come into contact with nearly as much water as a trickle filter. Outside the water column where most of the bacteria live there isn't a great deal of water flow. It happens very slowly. The areas that become anaerobic are extremely deep with hardly any flow, which is why they have the ability to become anaerobic in the first place.

First, one would have to assume that the great majority of waste is ending up in the bioball chamber. I don't see how this is possible, lots of detritus and waste accumulate on the rock, bottom of the tank, ect.

If this were true you would be able to remove a wet/dry with little impact on the biological state of the tank. The opposite is true.

Second, one has to assume that the conditions in the bioball chamber versus the surface area of the bioballs are that much more favorable as to create a situation where aerobic bacterial activity will cease in other parts of the tank.

I think you underestimate the importance of oxygen to aerobic bacteria. It isn't that they prefer lots of oxygen; they thrive in it. Bio-balls have very little surface area, you're absolutely right there. Because of the available oxygen they don't need much though. You'll find a much higher population of bacteria living on plastic bio-balls in a wet/dry than you will extremely porous material submerged in the tank. That increased air makes a huge difference.

not to mention the fact that the bacteria on the LR generally has the first crack at the waste and nutrients in the system, as much of it accumulates or is produced on or near the rock...

You're assuming the water will carry great volumes of waste through the rock and straight to the bacteria. That doesn't happen as quickly as you apparently think it does. You yourself have talked in great length about the "speed" in which wet/dry filters create nitrates. Why is that? It's certainly not because they grow "super bacteria" that work faster. It's because they come into contact with the waste at a faster rate.

This demonstrates exactly what I was saying, nitrate reduction in LR does not occur at the same rate as nitrate production in the system. If it did, I'd see zero nitrates....

In a tank that isn't completely cycled of course you'll have nitrates. The reason anaerobic bacteria take longer is because in order for them to remove nitrates you must first have a thriving population of aerobic bacteria. These aerobic bacteria will consume oxygen which will create an anaerobic zone for the new nitrate-consuming bacteria. Eventually though you'll have a population of both that will take care of ammonia, nitrites and nitrates. Grow the bacteria in a wet/dry and you won't have the population of aerobic bacteria necessary to create an anaerobic environment. This is where location comes into play.

Clayton

 

[Jiddy]

I just want to post somethin in an advanced topic

 

[clayswim]

That's a great point Jiddy, lol

Clayton

 

[mojoreef]

Well its a tough arguement as both of you are correct for the most point.

Bacterial populations are based on the ammount of food present in the tank. In the bacteria that you folks are talking about it would be nitrogen reducing bacteria. As per competition between BB and LR for ammonia/ammonium yes they are competitors and since thier is only so much ammonia/ammonium in the tank they will out compete themselves. Biolballs will win this battle as thier enviroment is better suited to them and they see more water (and thus more nutrients). This will cause a ripple effect also for the amount of denitrification. LR is a much better method as the denitrifiers are and hands length from the nitrifiers and migration of nitrogen is easy. Now with BB taking out an amount of nitrifing bacteria food source it will make the LR nitrifing bacterial population lower, which in turn will make the mean that the denitrifing bacterial population will thus be made lower as an effect of lower amounts of thier food source being present.
So if that is the question (will BB's out compete LR areobic bacteria) then the answer is yes. Its early here so I am not sure if what I wrote is understandable or not, lol

When looking at the whole nitrogen cycle you cant just draw a line from one function to another, thier are several routes that can and are taken, these differing routes are based on enviroments, and the presents of other components. It would take to long and be rather confusing to list all of the possible routes that can happen with in a nitrogen cycle so lets try to keep it simple for the sake speed here.
Nitrification is basically the sequential oxidation of ammonium ions to nitrate. This is done by two groups of bacteria (lithotrophic and organotrophic bacteria) to keep it simple thier end product is nitrate although they take both simular and different routes to achieve it and food input (for sake of an easy word) can be a number of different things, As in it doesnt have to be just ammonia, it can be ammonium, nitrite and slight off shutes from them.
From here we go to nitrate reduction. which is a process that happens in anerobic type conditions, not because the nitrate reducing bacteria cant live in oxygenated water (they can and perfer it) but because dissimilative nitrate reductase, the first enzyme in this nitrate reduction pathway, is derepressed only in the absence of oxygen. From here a series of other bacteria reduce it to nitric oxide gas, which is reduced to nitrous oxide gas, which is reduced to dinitrogen gas, which is released to the atmosphere. Most all of these processes have to do with both electron and proton swaping and/or removal.
Bacterial just dont jump onto a nitrogen component and begin eating it, they must create enzymes in order to perform these functions. Certain conditions will either allow or not allow these enzymes to be created. One condition is the presence of oxygen, this will not allow nitrate reducing enzymes to be produced thus none will occur, another is the presence of ammonia and ammonia represses assimilative nitrate reductase, the first enzyme in this nitrate reduction pathway, which is another reason DSB's dont export nitrogen based products from the tank but rather just keep cycling it.

Anyway I need more coffie, lol


Mike

 

[steve-s]

This may help some on the bacterial processes.....

http://www.cas.muohio.edu/~stevenjr/mbi202/cycles202.html

Cheers
Steve

 

[Boomer]

:lol: Well its a tough arguement as both of you are correct for the most point.

I could not agree more Mojo. The issue as your post shows is much more complex and just to be a tit-head let me throw in the a couple of curve balls, just to knock one out of their chair Dentiro's can also grow almost anywhere to some extent. They have been found to create their own environment, even right on plant "stems and "leaves". Then there are those little turds of bacteria that do more or less the whole cycle, no multi-step nitrif or denitrif cycle.....pick up NH3/NH4+ and covert it right to N2 gas

Also when comparing bioball trickle's to LR do not forget there is much more of lesser biofilm being created on bioballs. Bioballs are also not submerged either and water is trickling over them. With the thin biofilm the nitrate is literally being washed away. This is why they are so efficient, they do not get caught up in their own do-doo, which impedes nitrification and accelerates nitrification. If you put rocks in a trickle filter you would be surprised at result if left alone. It will turn into one giant bioflilm mess.


It would take to long and be rather confusing to list all of the possible routes that can happen with in a nitrogen cycle s

If I copied and posted this table in my bacter book it is so big and confusing Mojo's forum would shut down due to overload :lol:

 

[prow]

humm this sounds like the exact talk back when the berlin system first came about.

 

[clayswim]

I think what I was getting at originally was that wet/dry filters impede denitrification when compared to live rock only. After all these long messages in both threads I'm not even sure if MikeS agrees with that or not I guess the discussion was how it happens in the first place.

There are two reasons I believe this happens in live rock. One I mentioned above. As you go deeper into live rock the bacteria and other organisms consume enough oxygen to completely deplete it; thereby creating an environment suitable for denitrification. This is the same effect as a denitrifier reactor. The other point I should've made clearer but ran out of energy last night That's the fact that even if the anaerobic environment were in the rock with a wet/dry attached, the bacteria inside the rock would have very little nitrates to consume. This is due mostly to low water flow at those locations, which helps the environment. When the bacteria are right there creating the nitrates it gives far greater access to reduce them.

Clayton

 

[prow]

I think what I was getting at originally was that wet/dry filters impede denitrification when compared to live rock only.

no not at all. they dont impede it. if anything they aid with it. will expain below.

There are two reasons I believe this happens in live rock. One I mentioned above. As you go deeper into live rock the bacteria and other organisms consume enough oxygen to completely deplete it; thereby creating an environment suitable for denitrification.

yes. but its not so much the O2 as the CO2 levels. creating the envirornment. its more of a ph issue.

That's the fact that even if the anaerobic environment were in the rock with a wet/dry attached, the bacteria inside the rock would have very little nitrates to consume. This is due mostly to low water flow at those locations, which helps the environment.

well we are working with a closed system nitrates levels will not very that much even with in low flow areas. what will change is the availible O2=increased ph=anarobic bac to steal the O2 from the availible O2 rich complexes "the nitrates and nitrogen". this is why high production of nitrates doesnt impede it but aids it. however it is a slower proccess thus you get high nitrate levels, not that denitrification is impeded in any way. also if anything the aerobic bac will grow where the higher O2 is availible (the bio balls) leaving more surface area for the anaorabic bac. grow.

When the bacteria are right there creating the nitrates it gives far greater access to reduce them.

na not in a closed system.

 

[clayswim]

With all due respect Prow, your assumptions are incorrect. As I said before, it's the high concentrations of bacteria in the rock that create the anaerobic zones to begin with. "surface area" has nothing to do with it. To argue that wet/dry systems help denitrification is simply false. The end result speaks for itself.

Clayton

 

[prow]

With all due respect Prow, your assumptions are incorrect. As I said before, it's the high concentrations of bacteria in the rock that create the anaerobic zones to begin with. "surface area" has nothing to do with it. To argue that wet/dry systems help denitrification is simply false. The end result speaks for itself.

Clayton

i think you misunderstood everything i said.

 

[Boomer]

no not at all. they dont impede it. if anything they aid with it. will expain below

No, they will be impede it, as there is less proximity association and a lower diffusion gradient.

yes. but its not so much the O2 as the CO2 levels. creating the envirornment. its more of a ph issue.

Where did you get that from ? The issue is not really pH related, it is O2, light intensity and substrate concentration related more than anything. High nitrate levels can accumulate due to their rapid production in a trickle filter and low rate of denitrif, as there is little proximity association. High nitrate can also accumulate due to slow low nitrif rates coupled to the absence of a sink for nitrate in O2 waters. Nitrif bacts are also capable of denitro to a degree. Most of our nitros are not OAB(Obligated Aerobic Bacteria) but FAB (Facultative Aerobic Bacteria). And most of our denitro's are not ONB(Obligated Anerobic Bacteria) but FNB ( Facultative Anerobic Bacteria). Efficiency of nitrif---> denitro is a function of loading rates ( mostly DOC) and both are effected by these rates the same way ie, to little not good, to much not good. The biogeochemistry of aquatic sediments and their bact's is a very nasty subject. A book on the subject and I have three of them, will give you a headache.


O2=increased ph=anarobic bac

O2 has no effect on pH and anarboic, meaning anaerobic are bacts' that due not like O2 and high pH but low O2 and low pH ( if one wants to bring in pH)

na not in a closed system.

Why not ??

When the bacteria are right there creating the nitrates it gives far greater access to reduce them

 

[Boomer]

"surface area" has nothing to do with it

I will completely degree with that, as SA is a key factor in nitrif or denitrif.

 

[prow]

no not at all. they dont impede it. if anything they aid with it. will expain below

No, they will be impede it, as there is less proximity association and a lower diffusion gradient.

it is producing nitrates which feed the anaerobic bac. none the less. dosent impede it.

yes. but its not so much the O2 as the CO2 levels. creating the environment. its more of a ph issue.

Where did you get that from ? The issue is not really pH related, it is O2, light intensity and substrate concentration related more than anything. High nitrate levels can accumulate due to their rapid production in a trickle filter and low rate of denitrif, as there is little proximity association. High nitrate can also accumulate due to slow low nitrif rates coupled to the absence of a sink for nitrate in O2 waters. Nitrif bacts are also capable of denitro to a degree. Most of our nitros are not OAB(Obligated Aerobic Bacteria) but FAB (Facultative Aerobic Bacteria). And most of our denitro's are not ONB(Obligated Anerobic Bacteria) but FNB ( Facultative Anerobic Bacteria). Efficiency of nitrif---> denitro is a function of loading rates ( mostly DOC) and both are effected by these rates the same way ie, to little not good, to much not good. The biogeochemistry of aquatic sediments and their bact's is a very nasty subject. A book on the subject and I have three of them, will give you a headache.

ph is what breaks the bonds releasing the O2.

O2=increased ph=anarobic bac

O2 has no effect on pH and anarboic, meaning anaerobic are bacts' that due not like O2 and high pH but low O2 and low pH ( if one wants to bring in pH)

O2 affects the CO2 concentrations which affect the PH. typo should have said decrease the ph.

na not in a closed system.

Why not ??

When the bacteria are right there creating the nitrates it gives far greater access to reduce them

because in a closed system it just cycles the same water=same concentrations.

 

[clayswim]

Boomer, I meant surface area had nothing to do with his argument that live rock denitrifies better when used with a wet/dry filter. I should have worded it differently. You're absolutely right that it's important in the process itself.

Clayton

 

[prow]

never said it worked better.

 

[clayswim]

Prow, I think we're all a bit confused at to exactly what you're saying.

Clayton

 

[Boomer]

it is producing nitrates which feed the anaerobic bac. none the less. dosent impede it.

Yes but in a very, very inefficient way, so it is impeded

ph is what breaks the bonds releasing the O2.

That has very little effect in the micro world. About 1500 pages of advanced microbial biogeochemistry books and pH is nowhere in the discussion. It is not even in the indexes. But yes there is a pH limit for bacts. Like most living things in an aquatic environment there is a preferred pH, if and only if other parameters are met.

because in a closed system it just cycles the same water=same concentrations

That has little bearing on PA (Proximity Association). I hate to tell you this but the concentration is a closed system has a much greater variation in concentration than the real ocean. So if anything has the same concentration it is the ocean and not a reef tank.

O2 affects the CO2 concentrations which affect the PH

That is nonsense;
O2 has no effect on pH and pH has no effect on O2. And O2 has no effect CO2 and CO2 has no effect on O2. They are independent. CO2 will effect pH and vise-versa. Where did you get that from ??