Who doses potassium?

[Randy Holmes-Farley Verified Community Expert]

I did my first Triton test and they said I was low potassium, everything else was in order. I use the 4 part Triton method via dosser. I started to dos brightwell Chetogro based on element list of product. I figured my cheto was pulling out all my potassium. I been dosing 15 ml once a week in my 120 gallon.

Element list of brightwell cheto grow.
"Potassium - Protein synthesis, water and charge balance, enzyme activation.
Boron - Chlorophyll production, flowering, root growth, cell function.
Carbon - Required for all organic compounds.
Calcium - Cell wall stability and permeability, enzyme activation, cell response to stimuli.
Chlorine - Water and charge balance, photosynthesis.
Iron - Required for photosynthesis, component of enzymes utilized in redox reactions.
Magnesium - Component of chlorophyll, enzyme activation.
Manganese - Formation of amino acids, enzyme activation.
Molybdenum and Cobalt - Required for nitrate reduction.
Nickel - Enzyme activation, processing of nitrogenous material.
Sulfur - Component of proteins and the coenzymes that are involved with nutrient utilization and growth.
Zinc - Chlorophyll production, enzyme activation."

there’s really no obvious reason that organism growth necessarily reduces potassium. When you add foods you should be adding the potassium in those foods, same as they took up when growing.

If you feed potassium deficient foods, k may certainly decline. Dosing inorganic nutrients may also promote the decline.

but the biggest cause of a K drop may be use if a two part that lacks sufficient potassium to offset the salinity rise and correction effects.

 

[sayurasem]

there’s really no obvious reason that organism growth necessarily reduces potassium. When you add foods you should be adding the potassium in those foods, same as they took up when growing.

If you feed potassium deficient foods, k may certainly decline. Dosing inorganic nutrients may also promote the decline.

but the biggest cause of a K drop may be use if a two part that lacks sufficient potassium to offset the salinity rise and correction effects.

Hi Randy, could you elaborate on adding potassium to food? May I ask examples of potassium deficient foods? Also what is considered inorganic nutrients?

I’m having issues with my montiporas, mainly capricornis and palawensis. Capricornis are turning pale lighter color and palawensis turning brown. Digitatas and encrusting montis looks normal.

I use salifert to test potassium and it was off the chart (literally). It took 30 drops of reagent k3 to get my water sample blue. Assuming salifert potassium test kit chart is gradual, my potassium would be 200ppm.

 

[Randy Holmes-Farley Verified Community Expert]

I’d try the kit on some new salt water, and/or get an icp test before raising it thst much.

Inorganic nutrients in the context of this discussion means nitrate or ammonia, and phosphate.

I do not know what foods may be potassium [edited to correct a typo from phosphate] deficient, but I have a hypothesis that frozen foods that are rinsed may be.

 

[sayurasem]

I’d try the kit on some new salt water, and/or get an icp test before raising it thst much.

Inorganic nutrients in the context of this discussion means nitrate or ammonia, and phosphate.

I do not know what foods may be phosphate deficient, but I have a hypothesis that frozen foods that are rinsed may be.

Thank you for your reply. I tested new freshly mixed saltwater at 35ppt and tested the same. 30 drops equal to 200ppm potassium. I don’t have access to icp test but I will get one.

I just wanted to make sure, did you mean potassium or phosphate deficient?

 

[Randy Holmes-Farley Verified Community Expert]

Thank you for your reply. I tested new freshly mixed saltwater at 35ppt and tested the same. 30 drops equal to 200ppm potassium. I don’t have access to icp test but I will get one.

I just wanted to make sure, did you mean potassium or phosphate deficient?

I dont know what comment of mine you are asking about, but if quality new salt water tests 200 ppm potassium like your tank, it is most likely a testing issue, not a low potassium issue.

 

[sayurasem]

there’s really no obvious reason that organism growth necessarily reduces potassium. When you add foods you should be adding the potassium in those foods, same as they took up when growing.

If you feed potassium deficient foods, k may certainly decline. Dosing inorganic nutrients may also promote the decline.

but the biggest cause of a K drop may be use if a two part that lacks sufficient potassium to offset the salinity rise and correction effects.

I dont know what comment of mine you are asking about, but if quality new salt water tests 200 ppm potassium like your tank, it is most likely a testing issue, not a low potassium issue.

You mentioned “if you feed potassium deficient foods, k may certainly decline.” I asked what kind of food that are potassium deficient, but you reply with phosphate deficient food.

I’d try the kit on some new salt water, and/or get an icp test before raising it thst much.

Inorganic nutrients in the context of this discussion means nitrate or ammonia, and phosphate.

I do not know what foods may be phosphate deficient, but I have a hypothesis that frozen foods that are rinsed may be.

 

[Randy Holmes-Farley Verified Community Expert]

You mentioned “if you feed potassium deficient foods, k may certainly decline.” I asked what kind of food that are potassium deficient, but you reply with phosphate deficient food.

Sorry, phosphate was a typo. It should read potassium and I corrected it.

 

[sayurasem]

Sorry, phosphate was a typo. It should read potassium and I corrected it.

Ahh gotcha. Thank you

 

[serwobow]

there’s really no obvious reason that organism growth necessarily reduces potassium. When you add foods you should be adding the potassium in those foods, same as they took up when growing.

If you feed potassium deficient foods, k may certainly decline. Dosing inorganic nutrients may also promote the decline.

but the biggest cause of a K drop may be use if a two part that lacks sufficient potassium to offset the salinity rise and correction effects.

If you are removing organisms like chaeto or cyano from the tank, it seems like potassium could definitely deplete in the tank, since organisms actively take up potassium. The concentration of potassium inside a cell is in the range of 6000ppm. If you are removing alot of chaeto or other organism, it seems like that could deplete potassium. Feeding may replace that potassium, or not, as you said above.

 

[Randy Holmes-Farley Verified Community Expert]

If you are removing organisms like chaeto or cyano from the tank, it seems like potassium could definitely deplete in the tank, since organisms actively take up potassium. The concentration of potassium inside a cell is in the range of 6000ppm. If you are removing alot of chaeto or other organism, it seems like that could deplete potassium. Feeding may replace that potassium, or not, as you said above.

Yes, and no.

True, those organisms certainly take up potassium and remove it.

But if the N and P to make that new tissue comes from other, fed, tissues (e.g., fish food), then those additions bring in potassium, and for K to deplete requires that the tissues used as food have relatively less K per N and P, than do the organisms being exported. Why would that necessarily be true? Maybe because K is lost from burst cells in freezing and drying of foods, and using whole, fresh foods may reduce or eliminate that issue.

As an a priori argument, one might think that accumulating potassium might be just as common as depleting potassium, if whole, fresh foods make up the sources of all N and P in the tank. In fact, accumulation might be more common than depletion since some dissolved N and P that might otherwise get into organisms is exported by skimmers, GAC, etc, and hence the amount of tissue added in the tank would be a bit less than was fed.

Of course, if one is dosing N and P (other than foods), then there certainly may be a tendency to export K.

 

[serwobow]

Your a priori argument seems logical (that K should accumulate over time in many tanks) but its not like people are commonly reporting high K issues in their triton tests. Low K seems more common. Maybe because a substantial fraction of people currently keeping reef tanks are dosing N and/or P, and thus there is a net K depletion over time? I dose NO3, at about 5ppm per day to maintain about 30ppm, but P stays constant with constant feeding (about 10ppb), and K depletes, according to my test kits (maybe depleting 1ppm/day or thereabouts), so I re-boost it up every couple months with KCl. Since every organism in the tank will take up K,N, and P at a different rate, it is unlikely that any food is going match up just right with the depletion rates.

 

[Randy Holmes-Farley Verified Community Expert]

Your a priori argument seems logical (that K should accumulate over time in many tanks) but its not like people are commonly reporting high K issues in their triton tests. Low K seems more common. Maybe because a substantial fraction of people currently keeping reef tanks are dosing N and/or P, and thus there is a net K depletion over time? I dose NO3, at about 5ppm per day to maintain about 30ppm, but P stays constant with constant feeding (about 10ppb), and K depletes, according to my test kits (maybe depleting 1ppm/day or thereabouts), so I re-boost it up every couple months with KCl. Since every organism in the tank will take up K,N, and P at a different rate, it is unlikely that any food is going match up just right with the depletion rates.

I don't think enough people dose N and P to fully explain it, but IMO, fish food processing may well do so. Since most K is internal to cells, and not tightly bound, breaking open cells may cause it to be released during steps relating to water removal by filtering.

Cooking foods in water, for example reduces potassium:

https://doi.org/10.1111/jhn.12846

"Cooking in water, pressure cooking and cooking in a microwave oven reduced potassium levels in all food groups, particularly in cereals and derivatives, fruits and derivatives, meats and derivatives, legumes, and leafy and cruciferous vegetables. "

 

[schabiazabi]

Since every organism in the tank will take up K,N, and P at a different rate

Not really true. Pretty sure all plants on the planet outside of water take those 3 in the same proportions. As a matter of a fact plants can not take 1 of the 3 without taking the other 2. That's why people that fertilize with nitrogen only are kind of wasting money.

I don't see a single reason why an ocean would work otherwise. Planet is simple. Anything that grows is very consistent in how it works. Actually you can even make a bolder statement. The universe works the same since it's built from the same elements.

 

[Randy Holmes-Farley Verified Community Expert]

I don't see a single reason why an ocean would work otherwise. Planet is simple. Anything that grows is very consistent in how it works. Actually you can even make a bolder statement. The universe works the same since it's built from the same elements.

Well, there are many reasons that K, N and P are not depleted in a reef tank at a fixed rate because there are processes that consume one or two of these and not all three. Here are a few:

Denitrification removes N from the system while not removing K or P.

Skimming removes N and P and not K because N and P are often part of organics and K is not.

Binding of phosphate to calcium carbonate surfaces consumes P, but not N or K since they do not bind.

Binding of organics to GAC and other materials removes some N and P but not K.

Bones of fish contain a lot of P but little N and K.

Foods do not add N, P and K is a fixed rate, so the accumulation from them is not fixed.

 

[schabiazabi]

Well, there are many reasons that K, N and P are not depleted in a reef tank at a fixed rate because there are processes that consume one or two of these and not all three. Here are a few:

That might be true, but I was not referring to that. Was only referring to this: "Since every organism in the tank will take up K,N, and P at a different rate" - that statement is mostly likely incorrect in our universe, so therefore in our tanks.

Denitrification removes N from the system while not removing K or P.

This is most likely not true. If this would be true ocean would get out of balance.
This can only be true in an aquarium if your "denitrification" process relies on other chemicals. I tested this before for decades and my results are different.

 

[Randy Holmes-Farley Verified Community Expert]

That might be true, but I was not referring to that. Was only referring to this: "Since every organism in the tank will take up K,N, and P at a different rate" - that statement is mostly likely incorrect in our universe, so therefore in our tanks.



This is most likely not true. If this would be true ocean would get out of balance.
This can only be true in an aquarium if your "denitrification" process relies on other chemicals. I tested this before for decades and my results are different.

Again, you are assuming something that just is not true. There are wide divergences of uptake of these materials and removal from a reef tank or the ocean.

1. Denitrification is a process that takes usable N out of the system, converting it to N2. That happens in the ocean all the time. Individual organisms (mostly bacteria in hypoxic environments) perform denitrification.

Denitrification - Wikipedia

en.wikipedia.org

2. Nitrogen fixing takes N2 from the air and converts it to usable N in the ocean and in other environments, including reef tanks. Individual organisms such as cyanobacteria can take up N2.

Cyanobacteria - Wikipedia

en.wikipedia.org

3. Polyphosphate accumulating organisms take up and store large amounts of phosphate.

Polyphosphate-accumulating organisms - Wikipedia

en.wikipedia.org

4. Organisms with bones, such as fish, take much larger amounts of phosphate out of the system to make their bones.

 

[Randy Holmes-Farley Verified Community Expert]

This is most likely not true. If this would be true ocean would get out of balance.
This can only be true in an aquarium if your "denitrification" process relies on other chemicals. I tested this before for decades and my results are different.

In fact, if you look into the actual data for the ocean, potassium, being a major ion (like sodium, chloride, sulfate, calcium, and magnesium), is the same salinity-adjusted concentration around the world, and only varies by salinity.

N and P, on the other hand, vary a lot by location, and especially by depth.

Your assertion of getting out of balance is not sensible since we all know that corals use a lot of calcium and alkalinity, and not much potassium or sulfate, and yet those ions are conserved across the worlds oceans.

 

[schabiazabi]

Those are just assumptions that simply there is no proof for. The building blocks of everything growing are uptaken plus minus proportionally. There is no single coral or plant that takes all the sudden way more 1 of those 3. It's fine that N and P varies by ocean location. It does not disprove my statement. Sure fish take P to make their bones, so do humans, but both fish and humans also uptake N and K, and those 3 are still in proportion. You can't just eat potassium all day.

As far as denitrification goes in a reef tank. If I could explain this correctly, war would start in the hobby. Denitrification in a reef tank does not happen, or at least not at the rate people assume. All these things people repeat in the hobby is simply that a "repeat". Wanna see how it works? Take water from your tank that has Nitrates of like 100. Setup 3 tanks: Seal completely tank 1. Create opening of 3% for tank 2 (my tank), and leave tank 3 fully uncovered (most tanks in the hobby). Measure Nitrates after 1 month, 6 months and 12 months. You will be surprised how things actually work. In a sense ocean and reef tanks are simpler than is generally assumed.

Your assertion of getting out of balance is not sensible since we all know that corals use a lot of calcium and alkalinity, and not much potassium or sulfate, and yet those ions are conserved across the worlds oceans.

No. Calcium and every chemical gets into the ocean in different ways at different proportions, and it "leaves" differently, but at the rate/mechanism that keeps ocean water constant. I'm not sure if I'm explaining this correctly in words though.

Denitrification does not work the way it is assumed in the hobby. There is no magical removal of N without removal of other chemicals. But I'm not sure if I want to start that war. I tested this for decades and never took what was generally assumed at face value. So I do know denitrification at least in a reef tank is not done through bacteria (there maybe tiny denitrification done with bacteria), and I do know for sure N P K "denitrificate" together, so do other elements.

 

[Randy Holmes-Farley Verified Community Expert]

I'm not sure if I'm explaining this correctly in words though.

You seem to not be. Your arguments overall do not seem to fit well established science and do not make sense. There are clearly many mechanisms and examples of uptake of elements that vary by organism. if you do not believe that, fine.

 

[rtparty]

I think we found an ICP Analysis scientist