N/P reducing pellets (solid vodka dosing) - Split

[Aquarist007]

ThankCapn fro bring your observations and keeping this thread relevent. I apologize ahead of time for my rambling thoughts, I had back surgery last week and am still heavily medicated, so my thought process's are hindered.

Hi Jack
Hope you are feeling better.
My thoughts from the article--sorry for not returing your post earlier but IMO there should be a discussion of it which does not seem to have happened here.
1. From first hand experience I feel that the skimmers function is to remove dead bacteria from the system.
Now I believe that dead bacteria does not thrive in the bacteria film and thus the skimmer will be affective in reducing it
The article did not mention where the bacteria counts were just live bacteria, dead or a combination of both.
Thus it is difficult to conclude from that article that the skimmer is not affective in reducing the dead populations of bacteria.

2. We are aware that the bacteria exist and multiply etc in a biofilm. Again how is the measurement of this taken since these bacteria are not water borne.

3."My experience agrees somewhat, but do we want the flow so high that bacteria leave the reactor in large quantities from being sloughed off or do we want to contain them as much as possible? Only asking here, because I have run high flow and low flow and have recently been just running them in the bottom of a canister filter and have found no difference in keeping my parameters in check. High flow did however cause the pellets to lose size much faster."

This has been much in debate in my area(Southern Ontario)
Do you run the pellets in a reactor or cannister or just in a bag in the sump.
One very experienced reefer and respected colleague runs the pellets in a bag in the sump--when I questioned this he stated that in order for nitrate reduction the bacteria had to be in an anerobic condition and that this was negated by pellets moving quickly in an external reactor.

I would really appreciate a discussion by you and others on this point.

 

[Randy Holmes-Farley]

This has been much in debate in my area(Southern Ontario)
Do you run the pellets in a reactor or cannister or just in a bag in the sump.
One very experienced reefer and respected colleague runs the pellets in a bag in the sump--when I questioned this he stated that in order for nitrate reduction the bacteria had to be in an anerobic condition and that this was negated by pellets moving quickly in an external reactor.

I would really appreciate a discussion by you and others on this point.

There are at least two issues here.

The first is that for organic carbon dosing of any kind to work (and by that I mean reduce N and P), there need not be any anaerobic consumption of the organic. Simple aerobic growth of bacteria takes up a lot of N and P as they incorporate these into their tissues and then are exported or consumed by other creatures 9or just build up tissue mass in the system).

The second is that a biofilm may form on the pellet surface, and at the bottom of the biofilm, where the bacteria are actively degrading the pellets, oxygen may be in relatively short supply. In that case, nitrate may serve in place of O2, causing a larger reduction of nitrate than is proportional to the phosphate that is taken up. This is the traditional anaerobic respiration that takes place in live rock and deep sand, etc. So one need not necessarily have the water surrounding the pellets be low in O2 for anaerobic respiration to take place. However, it may (or may not) happen more extensively if the water does have reduced O2. In any case, that difference won;'t impact phosphate reduction.

 

[Mrmole]

great questions. I am also looking forward to the answers.

Hi Jack
Hope you are feeling better.
My thoughts from the article--sorry for not returing your post earlier but IMO there should be a discussion of it which does not seem to have happened here.
1. From first hand experience I feel that the skimmers function is to remove dead bacteria from the system.
Now I believe that dead bacteria does not thrive in the bacteria film and thus the skimmer will be affective in reducing it
The article did not mention where the bacteria counts were just live bacteria, dead or a combination of both.
Thus it is difficult to conclude from that article that the skimmer is not affective in reducing the dead populations of bacteria.

2. We are aware that the bacteria exist and multiply etc in a biofilm. Again how is the measurement of this taken since these bacteria are not water borne.

3."My experience agrees somewhat, but do we want the flow so high that bacteria leave the reactor in large quantities from being sloughed off or do we want to contain them as much as possible? Only asking here, because I have run high flow and low flow and have recently been just running them in the bottom of a canister filter and have found no difference in keeping my parameters in check. High flow did however cause the pellets to lose size much faster."

This has been much in debate in my area(Southern Ontario)
Do you run the pellets in a reactor or cannister or just in a bag in the sump.
One very experienced reefer and respected colleague runs the pellets in a bag in the sump--when I questioned this he stated that in order for nitrate reduction the bacteria had to be in an anerobic condition and that this was negated by pellets moving quickly in an external reactor.

I would really appreciate a discussion by you and others on this point.

 

[Aquarist007]

There are at least two issues here.

The first is that for organic carbon dosing of any kind to work (and by that I mean reduce N and P), there need not be any anaerobic consumption of the organic. Simple aerobic growth of bacteria takes up a lot of N and P as they incorporate these into their tissues and then are exported or consumed by other creatures 9or just build up tissue mass in the system).

The second is that a biofilm may form on the pellet surface, and at the bottom of the biofilm, where the bacteria are actively degrading the pellets, oxygen may be in relatively short supply. In that case, nitrate may serve in place of O2, causing a larger reduction of nitrate than is proportional to the phosphate that is taken up. This is the traditional anaerobic respiration that takes place in live rock and deep sand, etc. So one need not necessarily have the water surrounding the pellets be low in O2 for anaerobic respiration to take place. However, it may (or may not) happen more extensively if the water does have reduced O2. In any case, that difference won;'t impact phosphate reduction.

thank you--ask for help and you get the best:beer:

I am confused by the first answer. I was taught that within the nitrogen cycle that it was aerobic bacteria that converted ammonia to nitrites.
It was the anerobic bacteria --two strains-one converted nitrites to nitrates and the other nitrates to nitrogen gas.
From what I am reading aerobic bacteria also uptake nitrates?
I realize that is a very simplist view--but I am in the maintenance business and always geared filtration methods away from bioballs etc to live rock because it was the live rock that could support the anerobic bacteria to reduce the nitrates

 

[bertoni]

Nitrate is used as an oxidizer by anaerobic microbes, I think. Nitrogen is a macro-nutrient and I thought that many aerobic organisms can take up nitrate and use it for all the proteins and other nitrogen-containing compounds produced by growth.

 

[Aquarist007]

Nitrate is used as an oxidizer by anaerobic microbes, I think. Nitrogen is a macro-nutrient and I thought that many aerobic organisms can take up nitrate and use it for all the proteins and other nitrogen-containing compounds produced by growth.

I understand what you are saying as far as aerobic bacteria using "some" nitrates.It must be a very small amt in proportion used by anaerobic bacterize otherwise our systems could live on bioballs and we not need live rock, which we know is not true

 

[Randy Holmes-Farley]

Yes, bacteria growing anaerobically use nitrate both as an N source to produce their own tissues, and as a source of "oxygen", producing N2. Aerobic bacteria use it only for building tissues.

But, driving enough aerobic bacterial growth with an added carbon source can potentially drive N and P down if sufficient amounts are added.

 

[Aquarist007]

Yes, bacteria growing anaerobically use nitrate both as an N source to produce their own tissues, and as a source of "oxygen", producing N2. Aerobic bacteria use it only for building tissues.

But, driving enough aerobic bacterial growth with an added carbon source can potentially drive N and P down if sufficient amounts are added.

this is very very useful information---thanks very much:thumbsup::thumbsup:

 

[tntneon]

Yes, bacteria growing anaerobically use nitrate both as an N source to produce their own tissues, and as a source of "oxygen", producing N2. Aerobic bacteria use it only for building tissues.

But, driving enough aerobic bacterial growth with an added carbon source can potentially drive N and P down if sufficient amounts are added.

+1 ,again learned alot from you Randy :beer:
So one could conclude that when having High N your better of with more anaerobic condintions ( meshbag ) , as here the bactria consumes no3 for tissue buildup and needs no3 to asperate (o2)---> reducing it directly into N² gas.

-What are your thoughts concerning flow in a carbon driven reeftank (high or low) , i tend to think when having poor flow or a deadspot that bacteria and detrius sedements in that area .
And can act as a nutrient sinck.
So my thought are more flow when carbon dosing.

-last week i added some pellets that i contained in a jar filled with fresh water , that had been standing there for half a year.
Oh man did that stinks !!!!! the smell of rotten egg was immense and not healthy , i almost got nausea from it.
Outside i rinsed the pellets untill they didn't stink anymore , before adding in my reactor.
I didn't whitnessed any rotten egg smell.
Leaving me to think that enough flow is needed to prevent sulphuric gas (H²S aka rotten egg).
Once in the reactor they do there job in keeping everything in check.


greetingzz tntneon (John)

 

[Aquarist007]

+1 ,again learned alot from you Randy :beer:
So one could conclude that when having High N your better of with more anaerobic condintions ( meshbag ) , as here the bactria consumes no3 for tissue buildup and needs no3 to asperate (o2)---> reducing it directly into N² gas.

I believe we also could extrapolate if having nitrate problems ===add more live rock--somewhere in the system display tank, sump, refugium

 

[cherubfish pair]

Don't forget the nitrifying anaerobic bacteria in the liverock cannot be harvested for nutrient export. That's what protein skimmers do for the pellets. They harvest for nutrient export. Just my 2 cents.

 

[Randy Holmes-Farley]

Yes, more live rock can help denitrification, and adding organic carbon can as well, since that process may be carbon limited in many cases.

There may be many reasons to set a particular flow, but I'm not sure exactly how denitrification relates to flow. To much flow through sediments may make the water never become anaerobic, but a little will help bring organics and nitrate into the right areas.

 

[sirreal63]

Thanks Capn, I am better, still on pain meds but not as much. I was away this weekend and stuck using an ipad for posting, and wasn't going to try and type this much on it. There is no place like home.

Hi Jack
Hope you are feeling better.
My thoughts from the article--sorry for not returing your post earlier but IMO there should be a discussion of it which does not seem to have happened here.
1. From first hand experience I feel that the skimmers function is to remove dead bacteria from the system. I agree and I can see the difference in my skim when VSV or pellets are being used.
Now I believe that dead bacteria does not thrive in the bacteria film and thus the skimmer will be affective in reducing it Actually I don't think dead bacteria thrive in any conditions, they are, well, dead, but I understand what you are saying.
The article did not mention where the bacteria counts were just live bacteria, dead or a combination of both.
Thus it is difficult to conclude from that article that the skimmer is not affective in reducing the dead populations of bacteria. No they did not, but I don't think they counted the bacteria by hand, and could only estimate total amounts, both dead and living, I am not sure if they have the ability to differentiate between the two, so I read it as total bacterial count.

2. We are aware that the bacteria exist and multiply etc in a biofilm. Again how is the measurement of this taken since these bacteria are not water borne. Are you sure the bacteria are not water borne? If they were not then where does the bacterial bloom come from? Have I been falsely working under the assumption that bacteria are in the water and on all surfaces in the tank? It is my understanding that bacteria can be be water and air borne, which makes sense to a lay person.

3."My experience agrees somewhat, but do we want the flow so high that bacteria leave the reactor in large quantities from being sloughed off or do we want to contain them as much as possible? Only asking here, because I have run high flow and low flow and have recently been just running them in the bottom of a canister filter and have found no difference in keeping my parameters in check. High flow did however cause the pellets to lose size much faster."

This has been much in debate in my area(Southern Ontario)
Do you run the pellets in a reactor or cannister or just in a bag in the sump.
One very experienced reefer and respected colleague runs the pellets in a bag in the sump--when I questioned this he stated that in order for nitrate reduction the bacteria had to be in an anerobic condition and that this was negated by pellets moving quickly in an external reactor. I have run them in a fast moving reactor, a slow moving reactor and in the bottom of a canister filter with GFO and carbon. None of these have shown any difference in nutrient reduction, they all have worked the same. Early on before commercial entities began saying a reactor was the way to run them, people hung them in bags and open top containers and they worked and were not tumbling. I am not so sure that hanging them in a bag would produce anoxic conditions for any great length of time, oxygen is abundant in most reef tanks and is not a limiting factor, even in a bag in a sump there is water movement around and thru the bag and if nutrients are finding their way inside the bag, it almost makes some sense that oxygen is too. I don't think I would intentionally try and run them in true anaerobic conditions, but that may work to a degree as well as Randy has pointed out, but I would be afraid of the dangers of running them that way.

I would really appreciate a discussion by you and others on this point.

What got me looking into the way we are using these pellets is the flood of reactors on the market, some seem silly to me, and made me question it. Having used them in a variety of ways effectively, and remembering that when we started with them, people used them in numerous ways, and they seemed to work just as well. This led my feeble mind to wonder if we really needed to tumble them, my own experience did not prove that we did, as they do not tumble in my canister filter.

I look at videos like this, and wonder if it is an environment conducive to bacterial growth, or if it hinders them, and just grinds them up.
http://www.youtube.com/watch?v=m3ZXKWzJBEI&feature=player_embedded

http://youtu.be/m3ZXKWzJBEI

In my own fast moving reactor the pellets were losing size much more quickly than the slow moving one. I attributed this to friction, not increased bacterial growth and the nutrient levels remained the same whether they were moving fast or not at all. With the pellets crashing violently into each other, it would seem to not only slough off dead bacteria, but live ones as well. I am curious if anyone knows if it makes a difference in reality. Randy, I would enjoy your input on this, your knowledge is always welcomed, I think I have learned more from you than anyone on RC.

 

[Bugger]

There may be many reasons to set a particular flow, but I'm not sure exactly how denitrification relates to flow. To much flow through sediments may make the water never become anaerobic, but a little will help bring organics and nitrate into the right areas.

So you mean no oxygen correct. Is there a positve to having the pellets tumble or do you believe that it might have a negitive effect, Or do you not know.
Do these pellets work better in or out of a reactor. Will they still work to any effect in a overflo box.

 

[cherubfish pair]

I don't think vodka, vinegar, or sugar could lend themselves to denitrification as well as pellets if the proper flow directs the sloughed bacteria from the pellets into a skimmer's intake of water. The bacteria from vodka, vinegar, or sugar is not directed into a skimmer's intake of water for proper harvesting of nutrient export where the excess nutrients are contained in the tissues of these bacteria.

 

[bertoni]

The pellets seem to require a lot of flow to keep them from sticking together and forming anoxic zones. I'd stick to a reactor, personally.

 

[cherubfish pair]

I emailed Reef Dynamics again about his nano pellet reactor and he has more plans for it now.

Here is the email:

Thank you for your e-mail. We are currently preparing for the MAX trade show at the end of the month. It is possible that I will have a prototype of the Nano-BPR at the show, but at this time there is not an official timeline for release. It will be desgined for systems up to 50 gallons.



Please let me know if you have any further questions, I will be happy to help.

Sincerely,
<img title="signature image" alt="" border="0">
Jeff Macaré

 

[Bugger]

The pellets seem to require a lot of flow to keep them from sticking together and forming anoxic zones. I'd stick to a reactor, personally

I know your probally right although dont we want anoxic zones for the type of bacteria we want to grow,

 

[Randy Holmes-Farley]

In my own fast moving reactor the pellets were losing size much more quickly than the slow moving one. I attributed this to friction, not increased bacterial growth and the nutrient levels remained the same whether they were moving fast or not at all. With the pellets crashing violently into each other, it would seem to not only slough off dead bacteria, but live ones as well. I am curious if anyone knows if it makes a difference in reality. Randy, I would enjoy your input on this, your knowledge is always welcomed, I think I have learned more from you than anyone on RC.

Thanks!

I can certainly believe that fast tumbling makes the pellets disappear faster. I can think of a number of reasons, as you have mentioned, and which one or ones it is might be hard to determine. I'm not even sure whether a thicker coating of bacteria on the pellets would make the pellets break down slower or faster.

Part of that uncertainty comes from not knowing what is the limiting factor is the breakdown of the polymer into consumable smaller bits like monomers. Do these polymers hydrolyze even in the absence of bacteria, or do bacteria speed the process greatly, perhaps by locally lowering the pH (which is well known to accelerate the hydrolysis of such chemical bonds as hold the pellets together)? If so, how much is that pH lowering impacted by availability of nutrients and the thickness of the bacteria layer? A thick layer will hold in CO2 better, lowering the pH, but it might exclude nutrients like N and P from getting to the surface, slowing CO2 production. Simple hydrolysis of the compound itself will produce acidic conditions, and a thicker coating of bacteira may hold that in better, accelerating the process.

How localized is the effect to the very outer layer of material, or does it get weakened deeper into the plastic, allowing for the possibility of tumbling and bumping to break out larger chunks that might otherwise stay in place longer?

 

[sirreal63]

Isn't it great when questions only bring on more questions?

I am not sure there is one right answer, these products haven't worked exactly the same in everyone's tank. Some had zero nutrient reduction with them, others had bacterial blooms, heavy cyano, white bacterial masses covering the rock and tank, etc. Some of us have had them work exactly as liquid carbon, so I am not sure we will ever nail down a perfect formula for success.