low potassium

[Bruce Burnett]

ok Randy I have read where some people do not dose potassium and others that say they do. I have also read that the Zeo system uses it up. Some people state that their low nutrient systems seem to use up potassium faster than they import it not using the Zeo. My Red Sea test kit showed my levels at 320. I don't do water changes, it is a 300 gallon system. I am using a recirculating pellet reactor with all in one pellets. I had my Monti's lose color and lost a couple of acros which I thought were from a temp swing. It was not until I started adding potassium that the Monti's started coloring back up and actually one of the acro is recovering. My pellet reactor gets a hard white crust build up. Is this hard bacteria or is this where my potassium is going as I do not have this build up anywhere else in the system.

 

[Randy Holmes-Farley Verified Community Expert]

If that value is correct for potassium, I'd certainly suggest raising it. Montipora's seem especially sensitive. A product like this is inexpensive and should work fine:

http://www.iherb.com/Now-Foods-Potassium-Chloride-Powder-8-oz-227-g/777

IMO, there's not really as good of an understanding of potassium balance issues in reef tanks as the other major ions, but here's my expectation...

The potassium level in a reef tank will be the balance between the inputs and exports. It does not bind to rock or anything else the way phosphate does, and is not appreciably incorporated into coral skeletons.

In tissues, potassium is generally located loosely inside of cells. So growing organisms that add more cells will take up potassium.

Likewise, foods that add whole cells will add potassium. Pieces of shrimp, fish, fresh algae, etc. Notably, freezing foods (and drying them) may break cell membranes, releasing the potassium. If the frozen food is rinsed, the potassium may be washed away, so rinsing foods may be undesirable for this reason.

If you have a lot of tissue growth in the tank (bacteria, macroalgae, ATS, corals, etc.) then you will have substantial uptake. Whether that is more potassium than the foods used to provide the nutrients for that growth will depend on what foods are fed. Shimming that removes bacteria and other whole cells from the system will export potassium. So will taking out algae. If those are consumed by other organisms in the tank (tangs for algae, sponges for bacteria, etc.), the potassium is returned to the system.

In my tank, I never rinsed foods, and never saw potassium get depleted (I did 1% daily water changes). Neither kits nor Triton testing showed it to drop from NSW levels without any supplementing.

Here's my standard commentary on potassium:

Optimal Parameters for a Coral Reef Aquarium: By Randy Holmes-Farley
https://www.reef2reef.com/threads/o...-reef-aquarium-by-randy-holmes-farley.173563/

Potassium

Potassium is listed with the less critical parameters, not because it isn't important, but due to the fact that it does not get rapidly depleted in most aquaria. The majority of reef aquarists do not test for or dose potassium, and likely have adequate amounts from water changes alone. Potassium is important for cellular function, and generally is higher in concentration inside of cells than outside. In people, for example, nearly all of it is inside of cells, with very low concentrations present in the blood.

In marine systems, most cells of organisms have higher concentration of potassium in them than the surrounding seawater. That would make it seem that potassium would be depleted rapidly as organisms grow and add tissue mass, whether they are bacteria, microalgae, macroalgae, fish, or corals. However, there is quite a lot of potassium in seawater and salt mixes, and aquaria are typically being feed foods that also consist largely of cells that once contained potassium. Assuming these cells are not broken open and rinsed free of potassium, a large amount comes in with foods. So the net concentration of potassium in the tank will be a balance between the food and other inputs, and the uptake from tissue mass (whether it is exported or left in the tank).

A number of aquarists have found their aquaria are depleted in potassium and dose it to maintain natural levels. I've not found it to be depleted in my aquarium and I do not dose any. Some people associate depletion with organic carbon dosing to drive bacterial growth, but I've not seen that in my system (perhaps due to the foods that I choose to feed). Of those with depleted potassium, the primary symptom seems to be certain issues with SPS corals such as Montipora. Sometimes it is reported as poor growth and/or greyish coloration. I do not know if that really does relate to low potassium, but if you have such an issue, measuring potassium with a kit and dosing if necessary may be useful. I'd recommend maintaining about 380-420 ppm, but if it already is higher than that level, I would not do anything to try to lower it.

 

[Randy Holmes-Farley Verified Community Expert]

A hard white crust might be either bacteria (or other organism) of some sort, or calcium carbonate. You can distinguish these two by putting some in vinegar and seeing if it bubbles after a while. A small amount of bacteria "crust" wouldn't be a sink for a large amount of potassium. The concentration inside bacteria (if similar to most cells) might have only about 15 times as much potassium in them than seawater, so a small volume of bacteria only noticeably depletes a small amount of seawater.

 

[Bruce Burnett]

thanks Randy, just so you know vinegar did not react with the hard build up at all, was one of my first test.

 

[tcoyle]

Randy, with that potassium that you linked to, can you give me a a recipe to mix up. My monticaps are always greying out now and from my Triton testing a few months ago, I know I suffer from low potassium. Also what kit would you recommend for me to get to test with as it seems I am going to have to test more often then I thought.

 

[Randy Holmes-Farley Verified Community Expert]

Randy, with that potassium that you linked to, can you give me a a recipe to mix up. My monticaps are always greying out now and from my Triton testing a few months ago, I know I suffer from low potassium. Also what kit would you recommend for me to get to test with as it seems I am going to have to test more often then I thought.

Do you have a scale?

 

[Randy Holmes-Farley Verified Community Expert]

thanks Randy, just so you know vinegar did not react with the hard build up at all, was one of my first test.

Thanks for the info.

 

[tcoyle]

Do you have a scale?

Yes I do.

 

[Randy Holmes-Farley Verified Community Expert]

Potassium chloride is 52.3 % potassium by weight.

Add 10 grams into 1 L of fresh water. Ignore any nondissolving solids. This solution is 5230 ppm potassium.

Adding 1 mL per gallon tank water will boost potassium by 1.4 ppm.

 

[Bruce Burnett]

I am going to recheck my potassium with new reagents as the test I did last night showed below 320. I am also going to make one gallon of fresh salt mix and test it. If I figured correctly 21 grams will raised 300 gallons by aprox 10 ppm per day so to raise it by 80 ppm will require 168 grams or about 66 teaspoons total. I ordered 10 lbs of potassium chloride powder off of Amazon for $27.00 lots more than I should need.
I know this will raise salinity a bit but if the potassium is being consumed in someway the salinity should not drop should it? I ask as except for the skimmer there should not be a drop in salinity. But I am finding I have to adjust the salinity back up about once a month with about 1 to 1 1/2 cups of salt dissolved in tank water. I don't have any salt creep to speak of. I guess I should keep track of the amount of liquid I empty from skimmer each month. Thanks for your help

 

[Randy Holmes-Farley Verified Community Expert]

It won't raise salinity all that much. Boosting potassium by 100 ppm will boost salinity by 0.2 ppt, or only sg = 1.02600 to 1.02615.

I agree the skimmer is the most likely salt loss.

 

[tcoyle]

Potassium chloride is 52.3 % potassium by weight.

Add 10 grams into 1 L of fresh water. Ignore any nondissolving solids. This solution is 5230 ppm potassium.

Adding 1 mL per gallon tank water will boost potassium by 1.4 ppm.

Thanks so much! test kit arrives tomorrow so I can hopefully make more of an educated decision on what is going on with my potassium levels.

 

[Randy Holmes-Farley Verified Community Expert]

You're welcome.

Happy Reefing.

 

[Bruce Burnett]

so after reading the instruction on the red sea potassium kit, where it states put lid on vial and shake for 15 seconds, it means very vigorously. The second time it states that if you shake the vial so hard it foams the precipitate starts separating before you put it through the filter. This time the color change was very apparent and I am now over at 440. I was still low when I started dosing as I have added about 6 Oz over a month. I will watch and see how long it takes to drop to 380

 

[Fishinwall]

Following

 

[Randy Holmes-Farley Verified Community Expert]

so after reading the instruction on the red sea potassium kit, where it states put lid on vial and shake for 15 seconds, it means very vigorously. The second time it states that if you shake the vial so hard it foams the precipitate starts separating before you put it through the filter. This time the color change was very apparent and I am now over at 440. I was still low when I started dosing as I have added about 6 Oz over a month. I will watch and see how long it takes to drop to 380

Ok, let us know what you find for a depletion rate.

 

[Bruce Burnett]

Ok, let us know what you find for a depletion rate.

2 weeks now and no change

 

[Bruce Burnett]

A hard white crust might be either bacteria (or other organism) of some sort, or calcium carbonate. You can distinguish these two by putting some in vinegar and seeing if it bubbles after a while. A small amount of bacteria "crust" wouldn't be a sink for a large amount of potassium. The concentration inside bacteria (if similar to most cells) might have only about 15 times as much potassium in them than seawater, so a small volume of bacteria only noticeably depletes a small amount of seawater.

Well I flushed my pellet reactor and all that was left was a hard carbonate deposit. It took a bit before the vinegar reacted. After having the reactor back up a couple weeks it started getting an orange bacteria buildup and then the white precipitate again. I am using a kalk stirrer with my top off. When I checked my kalk it was 8.6, calcium was 420, ph 8.24 why the precipitate in the pellet reactor and not visible anywhere else except over flow strainers, no build up on pumps or heaters? Using all in one pellets. Thanks

 

[Fishinwall]

Potassium chloride is 52.3 % potassium by weight.

Add 10 grams into 1 L of fresh water. Ignore any nondissolving solids. This solution is 5230 ppm potassium.

Adding 1 mL per gallon tank water will boost potassium by 1.4 ppm.

Randy
My triton test says my K is at 293.90 mg/l so it is deviated by 106.10

My tank has a water volume of about 74 gal.
With you solution mix, how much should I put in daily and for how long?

 

[Randy Holmes-Farley Verified Community Expert]

Randy
My triton test says my K is at 293.90 mg/l so it is deviated by 106.10

My tank has a water volume of about 74 gal.
With you solution mix, how much should I put in daily and for how long?

Can you tell us how some of the other ions (sodium, calcium, magnesium, came out? That will tell us if the salinity is low and K could be raised by raising salinity.