raising potassium

[tmz]

Plants, animals and bacteria accumulate some and excrete it in a variety of ways ; some via renal obligate renal filtering whether it's excess or not .
However,it comes in too, with foods and salt mixes,in an apparently adequate supply to keep it right at least in my heavily stocked mixed reef system.

I haven't seen anything that suggests there is a sink for it in skeletal mass.It does,however , seem to play a role in limiting metabolic acids which can erode skeletal mass.

Originally Posted by Bilk
I guess water changes may be enough to maintain levels, but in the past, when not replenishing potassium and only relying on water changes, I did see it depleting.

How did you test for it or otherwise reach that conclusion?Foods add it too,btw


I think the more successful systems account for it.

Well, better systems try to account for many things. Most do quite well without K dosing.
Assuming K is low because bacterial populations are high via organic carbon dosing for example and exported via skimming is not really accounting for it. I made that assumption and was ready to dose it but then a new readable test kit indicated it wasn't needed even after years of removing a lot of bacterial laden skimmate.

I think corals use what they need and the rest just remains free within the solution. The link I provided above claims it can be a limiting factor for algae as it somehow competes with NO3 and PO4.

I don't get that. If algae are limited then coral symbionts or other organisms might also be limited at some excess level.

Erring on the high side for K assuming there is no adverse affect at an excessive level is also an errant assumption. Animals have to process out excess and it can be toxic leading to hyperkalimia and sometimes death if levels in the blood become too high. What levels would be harmful in a reeftank are unknown.

All in all I wouldn't dose it unless I could reliably test for it and be sure I was maintaining nsw levels.

 

[Bilk]

How about this comparison. Water is constantly needed in the cell right? Yet the amount of water in your aquarium isn't depleted by the cells using it. Every living cell in there contains water. But we don't have to keep replacing the water that the corals "used up". There is a difference between having some of something inside a cell and taking it permanently away where it will never be seen again. You have yet to provide evidence it is expelled once assimilated, only to be reused again. Comparing it to water is disingenuous. Corals respirate as well and utilize oxygen. If not replenished it depletes. True? Oxygen is a depleting element in the water just as potassium and other trace elements are.



Can't get into the full article this morning, but I am going to go out on a limb and say that the concentration of potassium in skeleton is very very very very small just given the methods they used to detect it. This may very well be true, but any utilization is diminishing the supply and from the Wiki article, potassium is clearly important to any living organism. It is also contained within the cell structure and as such is a building block of that cell. If the coral grows, thus producing more cells, then potassium is required for that and is incorporated into the cell, removing it from the water column.



Not saying it isn't depleted in your case. Only that it isn't going away anywhere in the cells of the animals you keep. It must be being exported somewhere.



Right, export is where it is being removed.
Well every system "exports" nutrients in the form of skimming bacteria and other nutrients that also have K incorporated in their cell structure. Alga, bacteria and their die-off are exported in one form or another or the system becomes overloaded. If K isn't replenished manually, then where does the makeup come from?

Corals uptake calcium at a greater rate than potassium, and maintaining it a specific level is a basic requirement. If not replenished to that specific level, do corals stop utilizing what is remaining? I don't know the answer to that. The same goes for other elements as well. If these elements are not within certain relative ranges, does calcification cease? Or does the coral use the element until the system is fully depleted of that element? My intuition tells me that at certain diminished levels, the coral stops utilizing them as there isn't the requisite level of concentration to fuel the system.

I know more evidence might be needed to determine just how important potassium is in coral development and growth, but it has a relatively large presence in seawater compared to other trace elements considered important for coral growth and coral health.

 

[tmz]

I don't think anyone thinks you don't need K in a reef tank. But it's prudent to know not guess at levels before dosing it . Hobby grade test kits have been pretty difficuclt to read and of questionable accuracy. Salt mixes and foods seem to provide plenty , ime.

 

[Bilk]

All good points. Maybe heavier feeding does keep K levels near or at NSW levels. It is clear though that K does diminish if not replenished. That quantity of utilization vs replenishment is however, unknown. If feeding is enough to satisfy K then maybe it's enough to satisfy the replenishment of other trace elements as well such as iron and strontium, but people do supplement those.

There is a relatively high concentration of potassium in seawater vs that of other trace elements we consider important. One has to believe it's there for a reason as nature is pretty conservative and efficient and wouldn't waste a resource. Maybe too little is know what concentration of K is the breaking point for healthy vs just surviving, in decline or not as robust as it should be.

I use the KZ test and the Fauna Marin test. Found the levels in my system dropping below 300. I have yet to try the Elos and Salifert kits and hear both are much better.

 

[tmz]

Many reports on the KZ test kit in threads in this forum indicate low readings persistently. The fuana marin is supposed to be better but your still interpretting shades of cloudiness. Some of the newer kits by Salifert and Red Sea offer a readalbe color change ( i have no way to speak to their accuracy though)

Potassium is not a trace element ;it's major (nsw is around 380ppm IIRC). If you are confident it's really low and you'e not satisfied with your ,there is no reason not to bring it up to nsw levels.Just be a little wary of the test kits.
Most tanks don't need strontium and rarely need iron. Water changes take care of most of trace element reqiurements. Most tanks have higher levels than natural seawatr without dosing
Personally I don't dose any trace or minor elements except a very little iodide, since it depletes rapidly in my tanks ,reads low on test kits and I have gorgonians that may have a special need for it. Tried some iron for a while but got a bit of browning on some corals and some nusiance algae growth.

I seem to recall that potassium inside cells is higher than outside . If so, it seems unlikely they are reaching that level by absorbing it from the water. Food likely plays a role .

 

[disc1]

Corals uptake calcium at a greater rate than potassium, and maintaining it a specific level is a basic requirement. If not replenished to that specific level, do corals stop utilizing what is remaining? I don't know the answer to that. The same goes for other elements as well. If these elements are not within certain relative ranges, does calcification cease? Or does the coral use the element until the system is fully depleted of that element? My intuition tells me that at certain diminished levels, the coral stops utilizing them as there isn't the requisite level of concentration to fuel the system.

I know more evidence might be needed to determine just how important potassium is in coral development and growth, but it has a relatively large presence in seawater compared to other trace elements considered important for coral growth and coral health.

Then where? You tell me. If you know something I don't then share...

I'm coming just from simple education in cell biology. I think any good basic sophomore level physiology text should suffice. But if you know of some potassium sink in the cell then tell us about it. Please. Inquiring minds would love to know.

 

[disc1]

The difference with oxygen is that it is consumed chemically. During respiration you break a molecule of oxygen down and those oxygen molecules become part of water and CO2. Now it isn't oxygen anymore. It is completely gone. But there is no process anywhere that chemically turns potassium into anything else short of nuclear reactions. So the only possible sink would be to make it insoluble. I can't think of one biologically relevant anion that form insoluble complex with potassium. If you know one please share it.

 

[Bilk]

The difference with oxygen is that it is consumed chemically. During respiration you break a molecule of oxygen down and those oxygen molecules become part of water and CO2. Now it isn't oxygen anymore. It is completely gone. But there is no process anywhere that chemically turns potassium into anything else short of nuclear reactions. So the only possible sink would be to make it insoluble. I can't think of one biologically relevant anion that form insoluble complex with potassium. If you know one please share it.

I didn't think this forum was to express dogma. I thought it was a place to discuss ideas so that we can all learn and improve upon what we're already doing.


Potassium

Description
Potassium is one of the electrolytes essential to the smooth running of the human body; in fact just about all bodily functions depend on it to some extent. It is also one of the most abundant minerals in the body, constituting 70% of the positive ions inside cells; the rest are a mixture of sodium, magnesium, calcium, arginine, and others. Potassium is distributed to the cells by a process of passive diffusion and is regulated by an enzyme called adenosinetriphosphatase together with the level of sodium concentration inside the cell. Potassium and sodium are antagonistic, which means that an imbalance of one will automatically cause an imbalance of the other; normally potassium should predominate inside the cell.

Now this is in reference to human physiology, however I suspect it is applicable to corals as well, based on this article in Scientific American.

Did Life's First Cells Evolve in Geothermal Pools?

Now if potassium exists within the "body" (coral), then as it increases in mass, I'd assume the amount of potassium in that "body" similar increases. I'm all for the idea that a good portion of that potassium comes from feeding, but it isn't a constant within the system as you suggest. It is utilized and it does not fully return to solution 100%. A fully stocked tank might have the need for supplementation over and above what feeding would provide and especially if employing carbon dosing.

This subject always ends up with the inclusion of Zeovit and then it's dismissed because Zeovit isn't the subject of the post. To me all Zeovit is a commercialized version of carbon dosing. Any reef system requires the same elements, whether it be Zeovit or a Berlin tank. All I was doing in responding to the OP was informing them that natural sewater has a generally specific level of potassium and that in my experience I found it to be a diminishing element. What was utilizing it and how? I can't be 100% certain, however it is an element that is required for coral health. That is indisputable. It's part and parcel of their metabolic function just as it apparently is for all live forms.

I've seen this discussion has come up numerous times here and the end result is always the same. It's dismissed as not being necessary without scientific data one way or the other.

I've found other links to information regarding the presence of potassium in cell structure and my guess is the potassium didn't arrive in those cells magically. Now whether or not it came from just feeding alone, that is unknown. Since every living organism in the tank utilizes potassium, there very well may be a sink and potassium may need to be monitored and maybe supplemented. Pretty much all I said from the beginning and I didn't suggest to the OP to willy nilly dose it.

I'm hear to learn like everyone else. My expertise is in architecture and construction, not physiology.

Edit:
A coral consists of more than just a skeletal mass. Actually it's more than just one animal. The soft tissue cells of the coral as well as the zooxanthellae have need for all the elements in the water including potassium. Well I'm just taking a guess at that but it sounds pretty reasonable doesn't it? So if corals are growing then the utilization of all elements increase. Just another guess.

 

[disc1]

I think we are both missing each others points so I'm going to try to summarize. If I get you wrong then correct me.

I'm saying that there are no insoluble forms of potassium in your tank or the tissue of the living things therein. So the total amount of soluble K in the system as a whole remains constant.

You are saying that as corals grow and make more tissue that there is less K in the water around them because the relative concentration of K is higher inside the tissue than outside.

So I think we can both agree that if corals weren't growing there would be no additional need for K. But your point that growing new tissue requires the selective concentration of K into that tissue is worth looking at.

So what is the concentration of K inside this tissue. So I don't have info on corals per se, but in higher life forms the average is on the order of a 100 to 200 meq/L inside. So let's assume that it is at least on the same order of hundreds of millimolar.

In seawater outside the cell the concentration is tens of millimolar.

So that is about a 10x concentration inside the living tissue. Or somewhere thereabouts.

So for every cc of living tissue you create, you are removing you are definitely lowering the concentration of K outside the cell. But by how much.

The math gets kinda of fuzzy here because i"m not real sure how to gauge the amount of tissue growing. Let's say it is a few cc's of tissue, out of a tank that may be several tens of thousands of cc's in volume. A 100 gallon tank is 380,000 cc's. If there is a 10x concentration going into the cell, then for every cc of tissue you generate, you deplete 10cc of the outside water. That looks like a reduction on the order of 1 in something like 100,000. Or something on the order of 0.001% per cc of tissue growth. That's on the order of nanomolar. You can't measure that at home.

Over a long time with absolutely no feeding or water changes bringing in or out potassium, you'd have to fill quite a large percentage of the volume of your tank with new living tissue before you're going to make an appreciable or measurable dip in K based on growth alone. But OK, if you go that long maybe you deplete a little bit of K from the volume of water outside the cell. And that is assuming no feeding, which I wouldn't think would be very conducive to that much growth.

Now take a tank like Tom's (TMZ). He has what I think we could call appreciable growth in his tank. I don't think anyone can argue that his tank isn't quite successful at growing coral. Yet he is not able to measure any appreciable loss of K in his system. Why? Because it is a tiny number that get's involved in new tissue growth. And old tissue doesn't take up any more K than it puts out.


I'm still interested to hear if you've found any insoluble forms of K. There might be one out there I'm not thinking of, but it definitely doesn't involve any biologically relevant anion. Those I can account for. KCl - soluble. KI - soluble, K2SO4 - soluble, K3PO4 - soluble, K2CO3 - soluble, etc. etc. etc.

If living tissue is using up K, then where is it going? Where? It can't just disappear. It is either being assimilated into something or it is being precipitated somewhere and neither of those happen. The K inside the cell is all soluble K. It is all dissolved in water. The same water that is moving in and out of the cell. It is never destroyed, that is impossible short of a nuclear reaction.

Is it possible that some tanks get depleted? Well sure. Is it something the average reefer needs to be concerned with? Unless you're doing something specific that removes it from the system then I don't see it.

 

[disc1]

I didn't think this forum was to express dogma.

No one has mentioned God yet. I don't think dogma is germane to the discussion.

 

[Bilk]

No one has mentioned God yet. I don't think dogma is germane to the discussion.

You might need a dictionary.

 

[Bilk]

I think we are both missing each others points so I'm going to try to summarize. If I get you wrong then correct me.

I'm saying that there are no insoluble forms of potassium in your tank or the tissue of the living things therein. So the total amount of soluble K in the system as a whole remains constant.

You are saying that as corals grow and make more tissue that there is less K in the water around them because the relative concentration of K is higher inside the tissue than outside.

So I think we can both agree that if corals weren't growing there would be no additional need for K. But your point that growing new tissue requires the selective concentration of K into that tissue is worth looking at.

So what is the concentration of K inside this tissue. So I don't have info on corals per se, but in higher life forms the average is on the order of a 100 to 200 meq/L inside. So let's assume that it is at least on the same order of hundreds of millimolar.

In seawater outside the cell the concentration is tens of millimolar.

So that is about a 10x concentration inside the living tissue. Or somewhere thereabouts.

So for every cc of living tissue you create, you are removing you are definitely lowering the concentration of K outside the cell. But by how much.

The math gets kinda of fuzzy here because i"m not real sure how to gauge the amount of tissue growing. Let's say it is a few cc's of tissue, out of a tank that may be several tens of thousands of cc's in volume. A 100 gallon tank is 380,000 cc's. If there is a 10x concentration going into the cell, then for every cc of tissue you generate, you deplete 10cc of the outside water. That looks like a reduction on the order of 1 in something like 100,000. Or something on the order of 0.001% per cc of tissue growth. That's on the order of nanomolar. You can't measure that at home.

Over a long time with absolutely no feeding or water changes bringing in or out potassium, you'd have to fill quite a large percentage of the volume of your tank with new living tissue before you're going to make an appreciable or measurable dip in K based on growth alone. But OK, if you go that long maybe you deplete a little bit of K from the volume of water outside the cell. And that is assuming no feeding, which I wouldn't think would be very conducive to that much growth.

Now take a tank like Tom's (TMZ). He has what I think we could call appreciable growth in his tank. I don't think anyone can argue that his tank isn't quite successful at growing coral. Yet he is not able to measure any appreciable loss of K in his system. Why? Because it is a tiny number that get's involved in new tissue growth. And old tissue doesn't take up any more K than it puts out.


I'm still interested to hear if you've found any insoluble forms of K. There might be one out there I'm not thinking of, but it definitely doesn't involve any biologically relevant anion. Those I can account for. KCl - soluble. KI - soluble, K2SO4 - soluble, K3PO4 - soluble, K2CO3 - soluble, etc. etc. etc.

If living tissue is using up K, then where is it going? Where? It can't just disappear. It is either being assimilated into something or it is being precipitated somewhere and neither of those happen. The K inside the cell is all soluble K. It is all dissolved in water. The same water that is moving in and out of the cell. It is never destroyed, that is impossible short of a nuclear reaction.

Is it possible that some tanks get depleted? Well sure. Is it something the average reefer needs to be concerned with? Unless you're doing something specific that removes it from the system then I don't see it.

I think you've only considered the idea that corals are the sole organism utilizing K. At least that's what I got from this last post. I believe the reason Zeovit recommends monitoring K and supplementing it is because of carbon dosing causing bacterial populations to deplete it via skimming.

Now if K doesn't exist at the levels corals are able to utilize it, then there's a problem. As I asked before, even when Ca drops below a certain level, do corals stop assimilating that as well? I think that's true. I don't believe they continue to utilize it at a constant rate until it's depleted. I think there's a point or level in which it is no longer available to them because of concentration. Maybe I'm wrong, but it does seem that corals do shut down and deteriorate from low levels of various elements.

 

[disc1]

I think you've only considered the idea that corals are the sole organism utilizing K. At least that's what I got from this last post. I believe the reason Zeovit recommends monitoring K and supplementing it is because of carbon dosing causing bacterial populations to deplete it via skimming.

Now if K doesn't exist at the levels corals are able to utilize it, then there's a problem. As I asked before, even when Ca drops below a certain level, do corals stop assimilating that as well? I think that's true. I don't believe they continue to utilize it at a constant rate until it's depleted. I think there's a point or level in which it is no longer available to them because of concentration. Maybe I'm wrong, but it does seem that corals do shut down and deteriorate from low levels of various elements.

Now you're arguing in circles. If you just like to argue then fine. I won't argue with you anymore.

Several posts back I said that export was the only way it was really going to get low and you argued that the corals somehow used this potassium up so that it was gone forever. Now you say I'm forgetting about export.

 

[Bilk]

Now you're arguing in circles. If you just like to argue then fine. I won't argue with you anymore.

Several posts back I said that export was the only way it was really going to get low and you argued that the corals somehow used this potassium up so that it was gone forever. Now you say I'm forgetting about export.

No what I said was it was being depleted in the system by what ever means, and that if not available in the range corals may need it to be, then it could be an issue. I didn't claim the corals utilized all the potassium that was depleted.

On the other hand you claimed the level of potassium was never diminished by any means in the system and that it wasn't an important element to be concerned with. That it was cyclical and remained in the system because it was utilized, expelled and reintroduced into solution.

I'm sure some of both ideas are correct and I'm also sure this wasn't meant to be an argument. It is supposed to be a discussion. I believe that is the intent of this forum. To share ideas and experiences, to ask questions and to hopefully gain a better understanding of what we're doing, in the hobby.

 

[tmz]

I don't think anybody said K is unimportant. It's nature is to remain constant unlike oxygen, nitrogen etc is what I'm hearing. I think the information David provided is informative and scientific and not dogmatic. I learned from it which is always a goal of mine in these discussions.
There are no leaps or assumptions ,just facts which give me less reason to consider dosing it. I've wanted to dose it just to see what affect it might have. The dogmatic marketing hype around some systems almost got me.
On the other hand a belief that dosing K is necessary or unnecessary,good or evil would fit the definition of dogma / doctirne or belief more. . The corals I have are colorful and grow well,fish and other animals are healthy,breed a lot and are long lived but I'm always looking for ways to improve. I doubt dosing K or minor or trace elements will do that and may in fact cause harm in excess not based on dogma but experience and facts,so , i choose not to.
I'm not sure why the focus is on absorbtion from the water anyway Though i think keeping natural sea water levels is prudent , assuming on ecan test for it accurately . Certainly calcium is taken that way for calification but what evidence is there that much if any K is absorbed vs eaten. It might be so but I haven't seen anything that actually says that uptake is predominantly from the surrounding water. I'd like to know that one way or the other. In any case regular water changes and feeding will keep it steady even when exporting lots of bacteria ,ime.Tanks may vary but most don't seem to need supplementation for K ,minor elements or trace elements beyond water changes and feeding.

 

[rbp 4 135]

On the ZEO site there is a fair ammount of talk that needle-wheel skimmers some how preciptate potassium. I thought I would throw this into the discussion, to see what peoples opinions on this are as I do not understand how it could happen.

 

[disc1]

On the ZEO site there is a fair ammount of talk that needle-wheel skimmers some how preciptate potassium. I thought I would throw this into the discussion, to see what peoples opinions on this are as I do not understand how it could happen.

I don't get that either. There aren't any insoluble form of K with any ions in seawater so I don't see how that would happen.

 

[tmz]

I can't think of a way that could happen.

 

[Bilk]

Well maybe someone can decipher what this means. I don't understand the jargon, it's not within the field of my expertise and am not inclined at this time to do the research. I also don't have full access to the paper. However in just this small paragraph, and the subject of the paper, it's intimated that K is somehow incorporated into the skeletal mass of corals. Again, I don't have the requisite background to fully understand what is being claimed.

Potassium and other minor elements in Porites corals: implications for skeletal geochemistry and paleoenvironmental reconstruction

Abstract
We investigated how the K/Ca, Na/Ca, Mg/Ca, and Sr/Ca ratios of powders ground from Porites coral skeletons are changed by cumulative chemical treatments to the powders: first with distilled/deionized water (DDW), next with 30 % H2O2 and then with 0.004 mol l−1 HNO3. The K/Ca, Na/Ca, and Mg/Ca ratios were decreased with the DDW treatment and then increased with the H2O2 and HNO3 treatments; the Sr/Ca ratio was slightly decreased through the cumulative treatments, suggesting fine-scale (tens of μm or less) elemental heterogeneities in the skeleton"”K, Na, and Mg are significantly enriched at the skeletal surface and also at the center of calcification (COC); in contrast, the heterogeneity of Sr is very small. We suggest that the principal mechanisms of K incorporation into coral skeleton are (1) ion incorporation into lattice defects/distortions and (2) ion adsorption onto crystal discontinuities (including crystal"“organic matter interfaces) as forms of K+ and KSO4 −. Furthermore, we measured the element/Ca ratios of a modern Porites coral skeleton along its growth direction at 2-mm intervals. Results showed that all the element/Ca ratios displayed annual cycles, that the K/Ca and Na/Ca ratios covaried with each other, and that the annual-minimum K/Ca and Na/Ca ratios coincided with the annual high-density band in the skeleton. It is unclear what environmental factors may cause the covarying annual cycles of the K/Ca and Na/Ca ratios; however, as a possible explanation, the cycles may be due not to environmental factors, but to a combined effect of (1) the K and Na enrichment at the COC, (2) annual bands of high- and low-density skeleton, and (3) mm-scale element/Ca measurements along the skeletal growth direction. This kind of effect on geochemical proxies of which the concentrations significantly differ between the COC and surrounding skeleton may generate false or distorted paleoenvironmental signals.

Again, all I stated was I witnessed K depletion in my tank from levels the raw ESV mix I use tested for. I assumed most of it was via the skimming of bacteria that was induced from the carbon dosing. However I also assume corals require K at some level, in the water column. To this point, I have yet to read a response that scientifically supports the idea that corals don't require K, or don't require it to exist within solution at a certain level for utilization, don't stop using it because the concentration is below a usable level or that the zooxanthellae are not utilizing it or are utilizing it and and cause the of depletion. Anecdotally, the only thing I have witnessed in other keepers tanks is how dosing has effected their corals while employing a carbon dosing scheme like Zeovit - claims of increased growth and better coloration with pictures they claim document this. That is all subjective of course.

 

[tmz]

Well maybe someone can decipher what this means. I don't understand the jargon, it's not within the field of my expertise and am not inclined at this time to do the research. I also don't have full access to the paper. However in just this small paragraph, and the subject of the paper, it's intimated that K is somehow incorporated into the skeletal mass of corals. Again, I don't have the requisite background to fully understand what is being claimed.



Zeovit - claims of increased growth and better coloration with pictures they claim document this. That is all subjective of course.

I can't extrapolate anything useful from it for this discussion. I don't have the whole study either. Seems like a pedantic detour.

It's a paleoenvironmental study as best as I can tell,probably trying to figure K levels in the past ocean waters. They suggest some K is adsorbed to places where organic interface with slektal mass occurs and to some odd lattice formations. Adsorbtion isn't surprising on a surface area of an old skelton but it isn't really incorporation or depletion( ie not a change in the element or a sink where it's removed from active interaction) as it can still react with other elements in the water. It's not buried in the crystal, I think. They also note it might be diffiuclt to draw inferences regarding paleoenvironmental reconstruction from the findings.
The other study you cited cites the presence of K in certain phases. I think that means it's moving through cycles .

Anecdotaly,organic carbon dosing systems don't necessarily deplete K. Coloration is complex but has much to do with other variables ( nutrient levels, salinity, temperature, oxygen levels, alkainity, food , lighting, flow and so on). Testimonials aside ,just adding K won't do anything for it as far as I can tell and most tanks shouldn't be deficient in it wether dosing organics or not.