Phosphate build up

[Witfull]

a new EQ will be established as the bacteria consume the Pi they will lock into their system Pi. but when they die and decompose the Pi will be released and then readsorbed by new bacteria. algae will also concume and recyle the Pi creating a new EQ (assuming we are not exporting. we will effectiveley created a more complex EQ. i am also not factoring deteriorization of sand due to enzymes. (witch would reduce the amount of binder)

 

[Witfull]

boy we are pouncing on this now!

 

[cwcross]

in the case of the weak Vs strong binding, will EQ still be in play? ie some Pi trying to bind to the .25 sand as well as the water or will the stronger binder literally lock the Pi untill a stronger binder or chemical/biological effect cause release?

Willful, this is an intuitive but difficult question. I was hoping no one would ask. OK...both equilibrium (binding) constants have to be fullfilled. To calculate the actual concentrations requires 3 equations and 3 unknowns. For instance we know that in the two flask sytem:

Pi(water)+Pi(sub1)+Pi(sub2)=1.0
Pi(sub1)/Pi(water)=0.25 and
Pi(sub2)/Pi(water)=1000

we can re-arrange and substitute to give

Pi(w)+0.25*Pi(w)+1000*Pi(w)=1
Pi(w)(1+0.25+1000)=1 or
Pi(w)=1/(1001.25)=9.99x10-4=.000999

then pi(s1)=0.25*0.000999 and
pi(s2)=1000*0.000999

to summarize

Pi(water)=0.000999 gm
pi(sub1)=0.00024975
pi(sub2)=.99999

Now I've sactificed some rouding errors here but you can get the idea. Both EQ's are enforced (they have to be). Most of the Pi is in substrate 2 very little is in the water and a little more is in substrate 1 than is in the water. Also, this whole model is a little oversimplified because to be accurate I would have to use the concentration of Pi in the water, not the mass. However, the concept is the same and it just takes a confusing step out of the math.

One mistake people make, and this is what I'm really trying to get you all to understand, is that the system is not static or slow and the molecules are never stuck on the substrate for very long...even in the case of extremely large binding constants. Molecules move FAST!!! Problem is that each time the Pi molecules try to shoot off in any given direction, they bump into a water molecule like a billiard ball. This slows them from moving from one side of the tank to another very fast because there are like trillions of water molecules in there all moving even faster than Pi, but the molecule itself is really in high gear. In fact the whole system is moving incredibly fast. The molecules are exhanging with the surfaces of the substrates millions of times per second/molecule or more. Its just on average that the ratio is 0.25 or 1000 or whatever. If we perturb the system, it will swing to its new EQ point very rapidly in the case of molecules and without biology. To look at this system in total, and accounting for all the water getting in the way, within minutes I would estimate.

 

[cwcross]

Ok, I think we can all agree that this is where the discussion is going to get complicated as biology is complex. So first I want to lay out a few points about cells and how they equilibrate and then set some ground rules for the discussion to progress. I've got to go to Miami day after tomorrow, and will be pretty busy until then and won't be back until Thursay evening with limited access to the net. Hopefully the discussion can go on without me and maybe I can log in before bed a little....Anway..

Cells and or a biological matrix WILL equilibrate. This just adds another "sink" or substrate so to speak to our discussion of equilibrium if we can just think of it simply.

Cell's (all cells) have complicated machinery that employ multiple individual equilibria to control or regulate the concentrations of thier nutrients inside the cell wall. They literally shuttle molecules back and forth through the cell wall via specialized enymes. The net effect is that as long as they are within certain established outside concentration boundries they can hold the Pi concentration inside themselves at EXACTLY the concentrations they like. So to some limited exent, it doesn't matter if the concentration of Pi outside themselves is 10 ppm or 50 ppm, they can hold thier internal Pi concentration, just where they want it. Of course if the external Pi concentration get's too high or too low, these regulatory mechanisms are overwhelmed and the cell will die eventually. For instance, if we could super skim the water over an established culture of cells such that the Pi concentration in water stayed at zero, the cells would eventually lose all their Pi and die. So in a way, we can consider a biological matrix as a strong sink or substrate that equilibrates very slowly with its environment. However to a large extent, the same rules of equilibrium we have been discussing apply. So, some ground rules:

The system is we have a single 100 ml of water in a flask with 10 grams of sand and we inroduced a single gram of Pi. We add no other food sources or sources of Pi and we export nothing.

What will happen?

Lets forget for the time being about fancy things like dissolving sand and H2S pockets etc. Lets just use a simple system and think about it.

After that then...Do we need an export system. If so, how can we extend this model to having a slow but constant input of Pi and also a system of exports?

What sort of export system or systems would work best.

Some things to think about. What limits are imposed on the populations of baceria and algea? Does the substrate itself impose any sort of limit? or is it just food that does? How do the algea and bacteria interact or compete?

Regards...Collin

 

[vjvl51]

Collin, you say, “What is the partioning coefficient with humic substances. I am quite sure it will be stronger than with limestone, but by how much?” From - http://welcome.to/humics/structurems/humicms.htm - “In this study it was found that humic acids bind to peptides and proteins, and can bind 10 times their own weight of clay particles, even solubilizing them.” This sounds quite a bit stronger than “partioning with the limestone will be very weak”. From these comments, I get the impression that worrying about limestone (ie dsb or lr) as a sink is, in your opinion, looking in the wrong direction – that we should be looking at removing humic acids – in other words the removal of as much decomposing matter as possible.

You say, “If the nature is such that the populations of bacteria and algea want to spiral out of control”. I was under the impression that bacteria and algae will grow only as long as there is a food source. At which point, some will start to die off, producing more food to sustain the remainder. This cycle happens until the amount of bacteria and algae is balanced by the amount of new food introduced to the system. This is when the system is balanced and only lasts as long as there are no changes to the amount of food. If this is true then bacteria and algae do not “spiral out of control” but are controlled by the amount of “food” that enters the system.

Vickie

 

[mojoreef]

Vickie food is just one of the ways that P and N comes into the tank. The addition of additives, SW mixes, the disolving of sand and so on and so on. The whole system is in a constant state of flux, rising and dropping as the sources enter, exit and change forms. The state of flux between bacteria and algae is not something that is out of control but the natural process of a system that is becoming nutrient loaded. the enviroment is skewing towards an enviroment more tothier liking so they will become more previlant.


Mike

 

[cwcross]

Vickie,

I'm glad somebody picked this thread back up..I thought it was dead. Ok. Please understand with this thread I am not trying to deliver an absolute answer to anything. My goal was and is to develop a fundamental understanding of the chemical equilibrium(s) at play in the aquarium regarding build up of unwanted actors. I started this with phosphate binding to limestone because it was simple. My goal was/is to work in the direction you are questioning.

Collin, you say, “What is the partioning coefficient with humic substances. I am quite sure it will be stronger than with limestone, but by how much?” From - http://welcome.to/humics/structurems/humicms.htm - “In this study it was found that humic acids bind to peptides and proteins, and can bind 10 times their own weight of clay particles, even solubilizing them.” This sounds quite a bit stronger than “partioning with the limestone will be very weak”. From these comments, I get the impression that worrying about limestone (ie dsb or lr) as a sink is, in your opinion, looking in the wrong direction – that we should be looking at removing humic acids – in other words the removal of as much decomposing matter as possible.

Yes, you are correct IMHO. Limestone itself falls into regime 1 of my model. Things in this regime will reach a static point that is easily balanced by export via water changes. Things in category or regime 3 (such as certain species with humic acids) will continue to build in the adsorbant because the binding constant is so strong that not enough of the species of interest will lie in the water to be removed by water changes. In this case, we need an export mechanism (other than skimming or water changes) that can control the phosphate tied up in regime 3. The question I pose to the board is..., exactly what constitutes regime 3???

You say, “If the nature is such that the populations of bacteria and algea want to spiral out of control”. I was under the impression that bacteria and algae will grow only as long as there is a food source. At which point, some will start to die off, producing more food to sustain the remainder. This cycle happens until the amount of bacteria and algae is balanced by the amount of new food introduced to the system. This is when the system is balanced and only lasts as long as there are no changes to the amount of food. If this is true then bacteria and algae do not “spiral out of control” but are controlled by the amount of “food” that enters the system.

Vickie

Ok, here I believe you are both right and wrong. Algea and bacteria populations will reach an equilibrium with the amount of available food (in this case we are only considering phosphates). If we just introduce the phosphate all at once, the bacteria/algea will grow until the food is consumed. At that point many will start to die off. As they decompose, much of the phosphate will be released back into the system to sustain more bacteria/Algea. So the system will be balanced as you suggest. However, we are continually introducing more phosphate via food and make up water. Since the B/A populations will basically bind up and hold nearly all the phosphate, their populations will continue to grow as long as we are adding food and make up water unless we can export them. So the trick is to export the phosphorous containing compounds in regime 3 somehow so we can truly balance the Pi at a reasonable level. You suggest one very good way to achieve that by removing detrius. Will this by itself solve the problem??? Why or why not??? What exactly are we removing when we remove detrius? What sort of P compounds will we remove?

What do you think..anyone else want to take a stab also??

Sincerely...Collin

 

[vjvl51]

Sorry didn't mean to post here

Vickie

 

[cwcross]

P.S. Vickie. Thank you for the great Humic acid link. As a point. I have personally investigated humic acids and other related extracts via NMR, LC/MS, UV and GC-MS in regard to their antioxidant properties. This was many years ago though....C

 

[mojoreef]

Yes, you are correct IMHO. Limestone itself falls into regime 1 of my model. Things in this regime will reach a static point that is easily balanced by export via water changes

I dont see how this is possible Collin. The area where the P is being released from the limestone is deeper in the sand bed (anaerobic region). This water will never reach an are where it can be changed up. It wont make it past either the bacteria or the Algae.

You suggest one very good way to achieve that by removing detrius. Will this by itself solve the problem??? Why or why not??? What exactly are we removing when we remove detrius? What sort of P compounds will we remove?

When removing detritus from the tank your going to get Dissolved inorganic phoshorus that has been bound up by bacteria as they will be present on the detritus/extra food in order to reduce it. Your also going to get Particulate inorganic phoshorus as it will be the detritus or part of its make up. Dissolved organic phosphorus will be a skimmer item if it has not been bound up yet, It also maybe available to WC's if not bound. The reason it may not be bound is that it is mostly animal waste so it might not be completely bound. then thier would be Particulate organic phosphorus entering the tank again as waste. It is quickly bound up but may be removed by either skimming or detritus removal.


Mike

 

[cwcross]

I dont see how this is possible Collin. The area where the P is being released from the limestone is deeper in the sand bed (anaerobic region). This water will never reach an are where it can be changed up. It wont make it past either the bacteria or the Algae.

I think I am not explaining myself clearly. Regime 1 is like a definition. By definition, things not strongly bound by a sink (in its most general sense) will exist most abundantly in the water column. Here they will be easily available for export. For instance, Nitrate might be a good example of something like this.

Things that display characteristics of regime 3 will be the opposite. They will exist most abundently in the sink and very little in the water column. These will not be available for export via water changes very effectively. Phosphorus in our aquaria would be more like this.

Also, P is being release everywhere all the time. Not just in the anaerobic region. It may be being released at a much greater rate in the anaerobic regionj, however, P will always be measurable in the water if the instrument you use to measure it is sensitive enough.

When removing detritus from the tank your going to get Dissolved inorganic phoshorus that has been bound up by bacteria as they will be present on the detritus/extra food in order to reduce it. Your also going to get Particulate inorganic phoshorus as it will be the detritus or part of its make up. Dissolved organic phosphorus will be a skimmer item if it has not been bound up yet, It also maybe available to WC's if not bound. The reason it may not be bound is that it is mostly animal waste so it might not be completely bound. then thier would be Particulate organic phosphorus entering the tank again as waste. It is quickly bound up but may be removed by either skimming or detritus removal.


Mike

Yes, I think that is accurate from my perspective. Detrius will be covered with bacteria which contain phosphorous in many forms. Also, the dead material itself will contain phosphorous in varies stages of decomposition. Some small amount of water soluble P will be released and could get skimmed or diluted via WC.

So the next question is, how effective is detrius removal towards the complete goal of managing P buildup?

 

[mojoreef]

I think I am not explaining myself clearly. Regime 1 is like a definition

Ahh Ok so then by definition it wouldnt really pertain in the aquarium??

So the next question is, how effective is detrius removal towards the complete goal of managing P buildup?

Tough question if your looking for numbers, but I would say it would constitute the largest portion of the equation. It is the point at which we can get P in a variety of different forms. Couple that with good wet skimming and you have a pretty effective meas by which to control it and break the cycle.

Mike

 

[cwcross]

Ahh Ok so then by definition it wouldnt really pertain in the aquarium??

It depends upon what you mean by pertain? In my opinion it is very pertinant, as it is a process which goes on all the time and drives most of what you see in the universe. I think you are having a hard time separating chemical equilibrium, as a general concept, to phosphate buildup in the sandbed. There are literally thousands of processes in our aquaria that will follow the thermodynamic rules of weak equilibria both chemical and biochemical. For instance, how is phosphate used biochemically for cells to derive energy? It is equilibrium of a relatively weak nature between orthphosphate and ATP via hydrolysis. In that sense, it is very pertinant. My point in illustrating 3 regimes is to fundamentaly define how equilibrium works and what the envelope of its characteristics can be. For instance, if a person asks why can Nitrate be effectively removed by water changes but not phosphate. The answer is because one follows rules of regime 1 binding whereas the other is more closely akin to regime 3. It is impossible to understand one accurately without understanding the other.

Tough question if your looking for numbers, but I would say it would constitute the largest portion of the equation. It is the point at which we can get P in a variety of different forms. Couple that with good wet skimming and you have a pretty effective meas by which to control it and break the cycle.

Mike

Maybe you are right. I don't know. However, I would guess that this will not break the cycle in and of itself unless you have a very well designed system. As you pointed out earlier, bacteria are very effective in re-using re-cycled phosphate. Unless one is syphoning detrius every day, I would put forth that it will only slow down the buildup of phosphate containing bacterial and algal cultures if one has a DSB. One empiricle observation that supports this statement is to observe that syphoning detrius will not stop the growth of macroalgea's. If syphoning detrius would by itself bring about a stable equilibrium concentration of Pi in the system then algal growth would have to stop as it would be resource limited. Thoughts? Another question. What is the average lifespan of a typical bacteria?

sincerely..Collin

 

[Maxx]

Hi guys.....sorry to stumble in late, but I've just spent an hour reading and attempting to understand all of this so bear w/ me if I sound confused....

What is the average lifespan of a typical bacteria?

As I can remember from my Micro-biology classes, hours usually, but many have impressive abilities to remain dormant for long periods of time. So if the turnover of bacteria (via life cycles) is pretty high, and the are very good at recycling P, than we have something is going to be constantly in flux, but never disappearing entirely, (assuming a sterile system still...adding Bios will ultimately increase the total population of bacteria due to increased food supply).
With regard to your references to regime 1-3...I'm understanding this to basically be stonger (3) or weaker (1) covalent bonds, correct?

If syphoning detrius would by itself bring about a stable equilibrium concentration of Pi in the system then algal growth would have to stop as it would be resource limited.

Pretty much everything is resource limited....no P or N, no algae.....maybe I'm overlooking the obvious here though. Has this conversation basically swung into trying to figure out the best way to reduce P levels in the aquarium?
Nick

 

[mojoreef]

I think you are having a hard time separating chemical equilibrium, as a general concept, to phosphate buildup in the sandbed

Your right my bad. I keep skipping ahead. I am looking at it in a different sence, more as the build up and filtration of P, compared to the deeper use of P. Ok I will get back on track

When I was refering to the P cycle again I was refering to the above. The complete cycle of P of coarse could never be broken. If it was most life as we no it would not exsist.

Unless one is syphoning detrius every day

Well the concept for say a BB tank is to keep the detritus in suspention. This allows the detritus to leave the tank via overflows and be skimmed out via the skimmer, set to remove wet skimmate.

If syphoning detrius would by itself bring about a stable equilibrium concentration of Pi in the system then algal growth would have to stop as it would be resource limited. Thoughts?

Thats a tough way of looking at it Collin. Thier are far to many things that will absorb and use P. Corals, gorgonians, corraline and so on will all use available P, also if you use LR it is used to maintain bacteria popluations. I guess it becomes a matter of how much availble P in this braoder cycle do you wish to have present in the tank. The removal of detritus keeps this ammount lower and more constant.


Mike

 

[cwcross]

As I can remember from my Micro-biology classes, hours usually, but many have impressive abilities to remain dormant for long periods of time. So if the turnover of bacteria (via life cycles) is pretty high, and the are very good at recycling P, than we have something is going to be constantly in flux, but never disappearing entirely, (assuming a sterile system still...adding Bios will ultimately increase the total population of bacteria due to increased food supply).

Hi Nick..welcome

I looked into this on the net last night after I posed the question. Evidently it is very difficult to answer what a true lifespan is because bacteria divide for reproduction. The question is normally addressed by the cell division rate. Thus cells can divide based on a period of a few minutes to a day or so. Some bacteria can go through as many as 29 generations in less than 7 hours. Thus population growth rates are exponential until some limiting factor comes into play.

With regard to your references to regime 1-3...I'm understanding this to basically be stonger (3) or weaker (1) covalent bonds, correct?

Yes basically, Except the bonding does not have to be covalent but can be and often is of the van-der-walls or electrostatic variety.

Pretty much everything is resource limited....no P or N, no algae.....maybe I'm overlooking the obvious here though. Has this conversation basically swung into trying to figure out the best way to reduce P levels in the aquarium?
Nick

I think the primary thrust of interest here is how to manage phosphate buildup. I originally started by trying to make a general model so that we could differentiate effective export mechanism between heavy metals, organic toxins, phosphates, nitrites etc. Heavy metals and Phosphates seem to be the prime targets with phosphate buildup being the first topic on the agenda. I think we have agreed, by taking the long scenic route, that phosphate will continue to build up in our sandbeds as long as we are adding food or other sources as it is closely akin to a sink with regime 3 characteristics. The question now is how to best deal with it?

Sincerely...Collin

 

[cwcross]

Well the concept for say a BB tank is to keep the detritus in suspention. This allows the detritus to leave the tank via overflows and be skimmed out via the skimmer, set to remove wet skimmate.

Yes, I would think that P buildup in a BB tank would be more easily dealt with by detrius removal. Rocks might eventually become saturated with P binding bacteria and start to grow hair algea but I don't know really

Thats a tough way of looking at it Collin. Thier are far to many things that will absorb and use P. Corals, gorgonians, corraline and so on will all use available P, also if you use LR it is used to maintain bacteria popluations. I guess it becomes a matter of how much availble P in this braoder cycle do you wish to have present in the tank. The removal of detritus keeps this ammount lower and more constant.

Mike

I love models and thought experiments so I'll pose another one. What do you suppose would happen if we had a clean aquarium that we put several inches of substrate in, a couple grams of Pi, a pinch of food, a microscopic amount of real live sand, and then sealed, except for a pure air supply. What would happen to bacteria and algea populations in this case over time? Lets focus on P and for the time being forget implications of nitrogen cycles and assume we can just breeze right through that.

Second question? Does the amount of room present in a rock or substrate serve to limit the populations of bacteria in any way? Or alternatively, what happens to bacteria colonies if they outgrow the substrate, or can this even happen?

Sincerely...Collin

 

[Scooterman]

Rocks might eventually become saturated with P binding bacteria and start to grow hair algea but I don't know really

This is why I'm thinking of a continued process of cooking rocks.

What do you suppose would happen if we had a clean aquarium that we put several inches of substrate in, a couple grams of Pi, a pinch of food, a microscopic amount of real live sand, and then sealed, except for a pure air supply. What would happen to bacteria and algea populations in this case over time? Lets focus on P and for the time being forget implications of nitrogen cycles and assume we can just breeze right through that.

Just a thought but eventually all the food would be processed & everything would die, taking it that this is a pure environment, other that what was introduced, including the air supply.

Second question? Does the amount of room present in a rock or substrate serve to limit the populations of bacteria in any way? Or alternatively, what happens to bacteria colonies if they outgrow the substrate, or can this even happen?

Yes, yes yes. without room to live I'd think just as any living organism, eventually the fight for space would be a factor.

 

[DonW]

This is why I'm thinking of a continued process of cooking rocks.

Ok so why use rock in the display at all. Why not large blobs of rock shaped acrylic. Can you glue coral to acrylic?? In a few months they would be covered in coraline. All the rock could be kept in a big sump with low light. You could use large 20lb pieces so that it could be boiled on a rotating basis.
Makes me sound like nut but in theory it would work.

Don

 

[Scooterman]

Actually that isn't that bad of an idea, I was thinking of the steps design, this would allow for awesome flow potential behind the steps, keeping your display spotless. On top of the stairs key pieces of LR would cover the surface area of the steps, sorta like the pipe rack I made for my tank.