Nitrate mystery

[Dan_P]

It seems logical to me, and while I cannot know the magnitude of the effect, I’m relatively confident it is real. Taken to an absurd extreme, the alternative view is that a vanishingly small amount of surface area will have just as much nitrifying capacity as a large amount of surface area.

There are many different organisms that will take up ammonia. They occupy different spaces in the aquarium. If one makes a large amount of real estate that is only available to microorganisms, microorganisms will be able to take up more and other organisms less, just like having 500 corals might take up more than a single coral of the same size.

The absurd extreme is absurd only when you don’t factor in that one needs to feed nitrifying bacteria more to have a larger nitrifying capacity, not increase surface area. You only increase the potential for more nitrifying bacteria growth by increasing surface area, not the capacity. For example, in a new aquarium, one doses more ammonia not surface area to increase nitrification capacity.

Of course other microorganisms take up ammonia, but again, unless you feed them more, there is not going to be a large increase in their biomass just because there is more surface area. And while 500 coral will consume more nutrients than one coral can, that one coral will never become 500 corals (or equivalent biomass) unless more and more nutrients are made available no matter how much the aquarium is enlarged.

I think the experiment to demonstrate this is one with an established nitrifying bacteria population. Double the surface area but don’t change the daily dose of ammonia. Does that aquarium’s consumption of ammonia increase? Or do the same thing with heterotrophic bacteria. Does adding more surface area with a constant feed rate increase the rate of oxygen consumption?

 

[Randy Holmes-Farley Verified Community Expert]

The absurd extreme is absurd only when you don’t factor in that one needs to feed nitrifying bacteria more to have a larger nitrifying capacity, not increase surface area. You only increase the potential for more nitrifying bacteria growth by increasing surface area, not the capacity. For example, in a new aquarium, one doses more ammonia not surface area to increase nitrification capacity.

Of course other microorganisms take up ammonia, but again, unless you feed them more, there is not going to be a large increase in their biomass just because there is more surface area. And while 500 coral will consume more nutrients than one coral can, that one coral will never become 500 corals (or equivalent biomass) unless more and more nutrients are made available no matter how much the aquarium is enlarged.

I think the experiment to demonstrate this is one with an established nitrifying bacteria population. Double the surface area but don’t change the daily dose of ammonia. Does that aquarium’s consumption of ammonia increase? Or do the same thing with heterotrophic bacteria. Does adding more surface area with a constant feed rate increase the rate of oxygen consumption?

I agree that an experiment would be very interesting, if difficult to design and implement.

I guess I’m not really understanding why this is not intuitively correct in principle. If any corals are getting ammonia, then there is ammonia available for more bacteria to take up available space. It’s not all being used by the existing bacteria, and if you then add more space for bacteria, some will take up the challenge and grow on the new space, using ammonia.

 

[Fish Fan]

Pardon me, and at risk of poking my nose through the ice hole like a seal in Eskimo country....

Wouldn't a big part of this conversation depend on the coral load of the tank?

The microbes will grow to whatever their limiting factor is. If you have a 50 gallon tank with one frag in the middle and a bunch of fish, a great percentage of the ammonia would go to the microbes. But in a more mature tank with much greater coral bioload, would there be a time when the corals could/would outcompete the microbes?

Is this why at Dan suggests that there's not a lot of nitrifier DNA in reef tank samples (that I assume are mature, coral tanks)?

Would this mean that in the early stages of a tank, the microbes are the important nitrifiers, and then as the tank matures with corals they become the primary consumer of ammonia?

I'd like to please ask again if there's a consensus on who are the microbial ammonia oxidizers in aquaria, bacteria and/or Archea? <This question is of particular interest to me.

Pardon me again if I have this wrong or am just late to the party

Thank you, smart people!!

 

[JonasRoman]

My tank is a mixed reef (leathers are the only thing not in here) and reads .08 phosphate and 0 nitrates and has for 6 months. All my coral are bright and happy and growing. I have zero pest algae or algae of any kind. I know not to chase numbers I just don’t want to bottom out and get issues.
I have all real pukani stone. Live sand bed about an inch and half thick. Tons of bio media in my sump. A fleece roller is my only mechanical filtration. I do 10% water changes every week. I use aqua forest pro hybrid salt. I dose microbacter 7 when I do my water changes. I dose pods and phyto here and there. And I dose Aquaforest 3-1 daily.
I feed twice a day. A frozen slurry twice a week. The rest of the time a mix of PE mysis, vitalis pellets, TDO, and hikari seaweed extreme. I also feed benereef twice a week.
Why do I have 0 nitrates?!
And maybe a stupider question to those much smarter than me but is it possible I do have enough nitrates and my system is just processing them so efficiently that it reads 0 but it’s there?
I figured by now I’d see some form of pest algae or problem but everything is for lack of a better term perfect.
Also how can I increase nitrate if I need to without increasing phosphate?

Its for me not mysterious at all. You have apparently enough with area for denitrification bacteria, and I am not surprised as you have both a decent sand bed and lot of biomedia in sump. So all nitrate that sooner or later are produced by the nitrification, is converted to N2 gas thanks to this. This is a no issue, be happy your denitrification is in balance with nitrate formation.

I would just be happy for that scenario and do nothing as long as everything looks good. As you seems have biological margins I would consider buying more fish.

 

[Dan_P]

I agree that an experiment would be very interesting, if difficult to design and implement.

I guess I’m not really understanding why this is not intuitively correct in principle. If any corals are getting ammonia, then there is ammonia available for more bacteria to take up available space. It’s not all being used by the existing bacteria, and if you then add more space for bacteria, some will take up the challenge and grow on the new space, using ammonia.

For a fixed amount of ammonia, the bacteria are likely in a stationary growth phase where growth rate equals death rate (predation too).. Adding surface area would not result in a higher growth rate and more bacteria stealing ammonia because food not surface area is limiting growth.

If true that more surface area does not increase the nitrifyer population, I wonder if the rate of ammonia capture by a biofilm increases. If more surface area spreads out the nitrifyer population, one could argue that an ammonia molecule would encounter a biofilm more often than a coral surface. The experiment I had in mind would measure ammonia draw down rate and might see this effect, though not detect population size differences. So what, right?

After your next reply, I will run experiment design details for your feedback, unless you totally deflate my balloon :-)

 

[Randy Holmes-Farley Verified Community Expert]

For a fixed amount of ammonia, the bacteria are likely in a stationary growth phase where growth rate equals death rate (predation too).. Adding surface area would not result in a higher growth rate and more bacteria stealing ammonia because food not surface area is limiting growth.

If true that more surface area does not increase the nitrifyer population, I wonder if the rate of ammonia capture by a biofilm increases. If more surface area spreads out the nitrifyer population, one could argue that an ammonia molecule would encounter a biofilm more often than a coral surface. The experiment I had in mind would measure ammonia draw down rate and might see this effect, though not detect population size differences. So what, right?

After your next reply, I will run experiment design details for your feedback, unless you totally deflate my balloon :-)

I guess I just don't agree with this assertion:

Adding surface area would not result in a higher growth rate and more bacteria stealing ammonia because food not surface area is limiting growth.

I'll say up front, we have no idea which organisms are actually taking up ammonia in an ordinary reef tank. Corals, bacteria, algae, and many species of each. Each will have somewhat different capabilities of taking up ammonia. That is, if we artificially lower ammonia more and more, some will drop out of the competition before others. So ammonia is not a hard and fast limitation at some fixed concentration that the tank stabilizes at, below which nothing changes. It's the mix of organisms taking it up that changes.

If any bacteria species are able to take ammonia at levels equal to or lower than corals, and if corals are actually getting any, then if we add more surface area, I think it is a perfectly viable hypothesis that more of the best ammonia scavengers will take hold and steal ammonia from corals. They could not do so to the same extent previously because space was limiting their ability to dominate the competition. But with space not a limitation, we can have more of the best scavengears that are able to beat out corals.

 

[Randy Holmes-Farley Verified Community Expert]

Pardon me, and at risk of poking my nose through the ice hole like a seal in Eskimo country....

Wouldn't a big part of this conversation depend on the coral load of the tank?

The microbes will grow to whatever their limiting factor is. If you have a 50 gallon tank with one frag in the middle and a bunch of fish, a great percentage of the ammonia would go to the microbes. But in a more mature tank with much greater coral bioload, would there be a time when the corals could/would outcompete the microbes?

Is this why at Dan suggests that there's not a lot of nitrifier DNA in reef tank samples (that I assume are mature, coral tanks)?

Would this mean that in the early stages of a tank, the microbes are the important nitrifiers, and then as the tank matures with corals they become the primary consumer of ammonia?

I'd like to please ask again if there's a consensus on who are the microbial ammonia oxidizers in aquaria, bacteria and/or Archea? <This question is of particular interest to me.

Pardon me again if I have this wrong or am just late to the party

Thank you, smart people!!

So I'm not addressing the amount of nitrifiers DNA data since I think it has plenty of caveats, including the one you pointed out about which organisms they actually are, and really a huge disconnect between measuring amounts of DNA and thereby quantifying the nitrifying capacity of microbes with that DNA.

It may well be true that corals can outcompete microbes. That is one of the big missing bits of data:

With one coral and one microbe in the same water, if we lower ammonia more and more, which falters first?


My hypothesis assumes there is an overlap between the corals and microbes taking up ammonia. If bacteria always get it all, or if corals always get it all, my hypothesis fails.

 

[JonasRoman]

Natural coral reefs have nitrate well below the detection limit of even the LR HannaChecker, so all organisms in your tank are perfectly capable of dealing with levels far below 0.25ppm NO3. As long as your corals are happy it's all good.
I don't think anecdotal evidence is worth much, but I personally ran a tank with undetectable nitrate levels for 5 years without issues and then decided to give ammonia dosing a try. I'm not sure if there is a positive effect yet.

If you decide you want to have some headroom so the tank doesn't get nitrogen limited or swarmed by dinoflagellates, I recommend dosing ammonia (https://www.reef2reef.com/threads/diy-ammonia-dosing-for-low-nitrate-systems.987087/)

Nitrate dosing doesn't make much sense imo, as corals (and pretty much everything else) prefers ammonia. Nitrate has to be converted back to ammonia first before it can fully be assimilated and this requires enzymes build from trace elements which are more likely to be a limiting factor then nitrogen.

100% agree. I posted in a parallell thread an article of the bad thing with nitrate already at 1 ppm...and good thing with ammonium.

 

[JonasRoman]

Thanks for the response. I will read what you sent.
Tons of biomedia is probably because of the freshwater tank keeping I’ve done for years. I was also under the impression that if I had a good amount of places for bacteria in combination with pods and phyto then it would work as a system reducing the need for tons of gear, chemicals, and other mechanical ways of filtration. Not to be frugal but to not get lost in the balancing act of a bunch of stuff that’s “overkill”.
When you say you’re not a fan are you saying you prefer to run no biomedia or just a light amount?

I think you should NOT remove the biomedia that apparently doing a perfect job. Even if its primary not anareobic purpose, thise biomedia will be after a while beneath the outer coatings. And reducing nitrate to N2 is never a bad thing, the coral,and the zooxanthelle will not starve. Its more dangerous with zero the po4 with unnatural ways like carbon source in water column or chemical filtration. But here you have a biological system that is very stable and mimics nature. Congratulations, do not change anything. And, you say the tank looks good=you (or the system) are doing right.

 

[Randy Holmes-Farley Verified Community Expert]

100% agree. I posted in a parallell thread an article of the bad thing with nitrate already at 1 ppm...and good think with ammonium.

I guess the questions are:

1. Does one know that the other sources of N that supply a large part of the N on a reef (ammonia, urea, and particulate foods) are present in any given reef tank in similarly sufficient quantities?

2. Is the low level of nitrate any risk for dinos in any given reef tank.

3. Are the acknowledged detriments of elevated nitrate (and phosphate) actually demonstrated in a reef tank in a way that a reefer would observe as a problem?

IMO, the answer to 3 is at best unknown, and likely minimal since tanks with 1 ppm phosphate and 100 ppm nitrate can be spectacular:

https://www.reef2reef.com/ams/randy’s-thoughts-on-nutrient-target-ranges.1087/
from it:

https://www.reef2reef.com/ams/randy’s-thoughts-on-nutrient-target-ranges.1087/

Figure 1. A very high nutrient system maintained by Richard Ross, with nitrate sometimes above 100 ppm and phosphate above 1 ppm. Details in this link:
https://www.reef2reef.com/threads/rich-ross-home-tank-guess-the-phosphate.296635/

 

[JonasRoman]

For a fixed amount of ammonia, the bacteria are likely in a stationary growth phase where growth rate equals death rate (predation too).. Adding surface area would not result in a higher growth rate and more bacteria stealing ammonia because food not surface area is limiting growth.

If true that more surface area does not increase the nitrifyer population, I wonder if the rate of ammonia capture by a biofilm increases. If more surface area spreads out the nitrifyer population, one could argue that an ammonia molecule would encounter a biofilm more often than a coral surface. The experiment I had in mind would measure ammonia draw down rate and might see this effect, though not detect population size differences. So what, right?

After your next reply, I will run experiment design details for your feedback, unless you totally deflate my balloon :-)

I agree with you, nothing bad will happen just becasue of increase surface area. The amount of bacteria will not increase, as long as the surface was not limiting. So in my mind its better to have more area than needed so the area never will be the limiting factor, a security margin. Now, when area is with margins, the systems bacteria will be limited by other factors, like nutrients, and thats the right way to get a balance. Always enough with bacteria to handle the nitrification and denitrification at a speed meaning there is no increase but a steady state=balance. Now you add a new fish, increase feeding, a short time of unbalance will occur, but as long as area are more than you need, a new balance will establish. If you restrict the area you will faster get into a scenario where bacterial population can not follow the increased biological load=unbalance in terms of rising nitrite and nitrate. So back to main question, 0 in nitrate (not true zero but probably between 0.5-1) meaning for me that your bacterial activity is in conguens with the nutrient input=balance.

 

[Randy Holmes-Farley Verified Community Expert]

I agree with you, nothing bad will happen just becasue of increase surface area. The amount of bacteria will not increase, as long as the surface was not limiting.

Sure. That's a logical truism. But we do not know that surface area is not limiting bacteria processes that take up ammonia when there is lots of tank ammonia being processed daily.

In any case, I cannot provide data that demonstrates biomedia is bad. It's just my hypothesis.

 

[JonasRoman]

I guess the questions are:

1. Does one know that the other sources of N that supply a large part of the N on a reef (ammonia, urea, and particulate foods) are present in any given reef tank in similarly sufficient quantities?

2. Is the low level of nitrate any risk for dinos in any given reef tank.

3. Are the acknowledged detriments of elevated nitrate (and phosphate) actually demonstrated in a reef tank in a way that a reefer would observe as a problem?

IMO, the answer to 3 is at best unknown, and likely minimal since tanks with 1 ppm phosphate and 100 ppm nitrate can be spectacular:

https://www.reef2reef.com/ams/randy’s-thoughts-on-nutrient-target-ranges.1087/
from it:

https://www.reef2reef.com/ams/randy’s-thoughts-on-nutrient-target-ranges.1087/

Figure 1. A very high nutrient system maintained by Richard Ross, with nitrate sometimes above 100 ppm and phosphate above 1 ppm. Details in this link:
https://www.reef2reef.com/threads/rich-ross-home-tank-guess-the-phosphate.296635/

3) The study was not in ocean but an experimental setup. So more like a aquarium situation. They emphasis also that ammonium has opposite effect, could protect coral from oxidative stress.
2) I do not know but I do not think low nitrate is dangerous for giving dino. I have had dino during very different situations, and more that when dino appears, no3 and po4 will decrease as it consumes this very fast. So hard to know for sure what is coming first?
1) I think ammonium is a good supplier in the tank for corals and the zooxanthelles, as we have a fish load (ammonium producer) that is very much above the ocean if you count fish/litre.

 

[JonasRoman]

Sure. That's a logical truism. But we do not know that surface area is not limiting bacteria processes that take up ammonia when there is lots of tank ammonia being processed daily.

In any case, I cannot provide data that demonstrates biomedia is bad. It's just my hypothesis.

Agree with that, that IF area really is limiting, an increase of biomedia will for sure increase nitrification. Your idea is interesting, that nitritfication bacteria will steal the valuable ammonia from the coral. But in your scenario, if I understand you, is that you want to have a nitrification that is lower than the production of ammonia? Isnt that a little dangerous setup, as you cant know where this unbalance could be out of control, and leading to for instance too much algue? or maybe overnutrition for the zooxanthelle?

 

[Randy Holmes-Farley Verified Community Expert]

Agree with that, that IF area really is limiting, an increase of biomedia will for sure increase nitrification. Your idea is interesting, that nitritfication bacteria will steal the valuable ammonia from the coral. But in your scenario, if I understand you, is that you want to have a nitrification that is lower than the production of ammonia? Isnt that a little dangerous setup, as you cant know where this unbalance could be out of control, and leading to for instance too much algue? or maybe overnutrition for the zooxanthelle?

I agree that there are unknowns, but I do not think ordinary reef tanks ever get into the scenario of insufficient surface area since there is plenty of rock and sand surface. There are many, many tanks with no biomedia, and I have never once see an ordinary tank have an ammonia "problem" absent a sudden surge from a dead creature of sand disruption and similar events.

Even frag tanks with little rock or surface area seem to do fine.

 

[Fish Fan]

Its for me not mysterious at all. You have apparently enough with area for denitrification bacteria, and I am not surprised as you have both a decent sand bed and lot of biomedia in sump. So all nitrate that sooner or later are produced by the nitrification, is converted to N2 gas thanks to this.

Excuse me again, smart reefers, but I have another relevant question that I've been wondering about for a long, long time now.

Is denitrification, as Jonas is describing here, actually possible in typical home aqaria?

I'm asking because of something the late Miami Reef posted sometime ago and it kind of stuck in my head:
https://www.reef2reef.com/threads/running-high-nitrates-but-zero-phosphate.1121604/post-13753315

From the above link Miami Reef wrote:
"Denitrification in a reef tank is a paradox.

In order to have it, you’d need flow so low that O₂ won’t significantly get in, but if you are limiting O₂’s entry point, how do you expect nitrate to get into those deep zones?"

So my questions would be; again, is denitrification possible in home aquaria? If so, how deep/dense would the rock/sand/bio media have to be to achieve a hypoxic or anoxic environment to facilitate denitrification? If Miami Reef is right and the nitrate cannot "flow" to these low 02 zones, would it diffuse to them, or is that basically saying the same thing (flow vs. diffuse)?

And Jonas, how can you be sure that the OP's extra bio media was of sufficient depth and density so as to create a low O2 environment? In my experience, when someone says that they added extra biomedia, they are usually talking about a relatively thin brick or some plastic bioballs, etc. I don't believe these will result in denitrification.

Thank in advance for your help, everyone!

 

[Randy Holmes-Farley Verified Community Expert]

Excuse me again, smart reefers, but I have another relevant question that I've been wondering about for a long, long time now.

Is denitrification, as Jonas is describing here, actually possible in typical home aqaria?

I'm asking because of something the late Miami Reef posted sometime ago and it kind of stuck in my head:
https://www.reef2reef.com/threads/running-high-nitrates-but-zero-phosphate.1121604/post-13753315

From the above link Miami Reef wrote:
"Denitrification in a reef tank is a paradox.

In order to have it, you’d need flow so low that O₂ won’t significantly get in, but if you are limiting O₂’s entry point, how do you expect nitrate to get into those deep zones?"

So my questions would be; again, is denitrification possible in home aquaria? If so, how deep/dense would the rock/sand/bio media have to be to achieve a hypoxic or anoxic environment to facilitate denitrification? If Miami Reef is right and the nitrate cannot "flow" to these low 02 zones, would it diffuse to them, or is that basically saying the same thing (flow vs. diffuse)?

And Jonas, how can you be sure that the OP's extra bio media was of sufficient depth and density so as to create a low O2 environment? In my experience, when someone says that they added extra biomedia, they are usually talking about a relatively thin brick or some plastic bioballs, etc. I don't believe these will result in denitrification.

Thank in advance for your help, everyone!

In my opinion, we do not have much info on the extent of denitrification in a reef tank.

If it is significant, it is likely only when organics are buried by some agent like an organism, and not simply from diffusing into low O2 regions since such diffusion will be slower than O2 diffusion.

 

[Fish Fan]

In my opinion, we do not have much info on the extent of denitrification in a reef tank.

If it is significant, it is likely only when organics are buried by some agent like an organism, and not simply from diffusing into low O2 regions since such diffusion will be slower than O2 diffusion.

Thanks for your help, Randy, I appreciate your time!

 

[Dom]

This tank looks great. Don't fix what isn't broken.

 

[ReneReef]

Excuse me again, smart reefers, but I have another relevant question that I've been wondering about for a long, long time now.

Is denitrification, as Jonas is describing here, actually possible in typical home aqaria?

I'm asking because of something the late Miami Reef posted sometime ago and it kind of stuck in my head:
https://www.reef2reef.com/threads/running-high-nitrates-but-zero-phosphate.1121604/post-13753315

From the above link Miami Reef wrote:
"Denitrification in a reef tank is a paradox.

In order to have it, you’d need flow so low that O₂ won’t significantly get in, but if you are limiting O₂’s entry point, how do you expect nitrate to get into those deep zones?"

So my questions would be; again, is denitrification possible in home aquaria? If so, how deep/dense would the rock/sand/bio media have to be to achieve a hypoxic or anoxic environment to facilitate denitrification? If Miami Reef is right and the nitrate cannot "flow" to these low 02 zones, would it diffuse to them, or is that basically saying the same thing (flow vs. diffuse)?

And Jonas, how can you be sure that the OP's extra bio media was of sufficient depth and density so as to create a low O2 environment? In my experience, when someone says that they added extra biomedia, they are usually talking about a relatively thin brick or some plastic bioballs, etc. I don't believe these will result in denitrification.

Thank in advance for your help, everyone!

Exactly, we can not assume that reduction in nitrate or undetectable nitrate is due to nitrification.

I agree with Randy, that if it’s happening it is unlikely to contribute much a in typical reef tank.