Potassium is always low. Dosing options and why?

[ItsAName]

Whenever I measure my potassium, it is always low. I've measured with my home kit and using Triton.

1. What is absorbing all of my potassium?
2. What's an inexpensive way to dose it? Triton dosing for potassium gets expensive quick.

 

[Cnidoblast]

https://www.amazon.com/10-Pounds-Potassium-Sulfate-Organic/dp/B008NWUXL8/

Potassium sulfate is rather cheap but I have no clue if the high sulfate ion content will harm anything @Randy Holmes-Farley

 

[jwshiver]

I have used this with no problems. 1ml per 25 gallons. I have to dose every day because the Zeolite stones suck it up. That is an assumption because I never had to dose it before I started using Zeolite a few years back.
https://www.bulkreefsupply.com/korallen-zucht-pohl-s-k-balance-potassium-strong.html

 

[Randy Holmes-Farley Verified Community Expert]

Whenever I measure my potassium, it is always low. I've measured with my home kit and using Triton.

1. What is absorbing all of my potassium?
2. What's an inexpensive way to dose it? Triton dosing for potassium gets expensive quick.

If you are using a diy two part, that will likely deplete potassium due to the effect of riding salinity that you keep resetting to normal.

 

[Randy Holmes-Farley Verified Community Expert]

Lots of people use food grade potassium chloride:

https://www.iherb.com/pr/Now-Foods-...pPtA3AqkANy34mv_t-8aAoB_EALw_wcB&gclsrc=aw.ds

 

[PSXerholic]

I typically use the Brightwell Potassion dry good. Relatively reasonable since you do your own stock solution for dosing and with a Salifert Potassium kit you can easily get a ballpark number where you are in order to calculate quick a correction dosage.

 

[PSXerholic]

Concerning the consumption, I notice from feedback from others, that folks that use high efficient nutrient reduction methods and as a result run in ULNS ranges have low potassium.
Also liquid bacteria products to clean the tank seem to have this problem.
A lot of bacteria products and the method of bacteria overpopulating nutrient reductions such as VSV, Zeostart, Vodka only, certain bio pellets seemed to be linked to this.
It is apparently in the nature of some bacteria to utilize more potassium than others, hence you must watch out for this.
What I'm saying is that bacteria using K as well ;-)

I personally had crazy K consumptions when excessively using liquid carbs to get nutrients down.

 

[ItsAName]

Lots of people use food grade potassium chloride:

https://www.iherb.com/pr/Now-Foods-...pPtA3AqkANy34mv_t-8aAoB_EALw_wcB&gclsrc=aw.ds

Any thoughts on how to make this match the dosing for Triton? When I send in the reports to Triton they'll say, "add 60ml of potassium"

 

[Randy Holmes-Farley Verified Community Expert]

Any thoughts on how to make this match the dosing for Triton? When I send in the reports to Triton they'll say, "add 60ml of potassium"

Not unless you can get them to say what the concentration is.

If you need a particular potassium boost, we can advise that.

 

[ItsAName]

Not unless you can get them to say what the concentration is.

If you need a particular potassium boost, we can advise that.

Actually, I can use their recommendation for a boost and we can compare

To go from 351 mg/l to 400 mg/l potassium, they recommend 214ml over 4 days (so 53.5ml per day for 4 days)
Another example, to go from 342 mg/l to 400 mg/l potassium, they recommend 253.4ml over 4 days (so 63.4ml per day for 4 days)

Using that, can you figure out how to make a concentration equal to theirs using the Now Potassium Chloride?

When I measure potassium it's usually around 350ml too with the salifert kit.

Excuse my ignorance, but not being pure potassium and being potassium chloride, is that an issue?

 

[Randy Holmes-Farley Verified Community Expert]

Actually, I can use their recommendation for a boost and we can compare

To go from 351 mg/l to 400 mg/l potassium, they recommend 214ml over 4 days (so 53.5ml per day for 4 days)
Another example, to go from 342 mg/l to 400 mg/l potassium, they recommend 253.4ml over 4 days (so 63.4ml per day for 4 days)

Using that, can you figure out how to make a concentration equal to theirs using the Now Potassium Chloride?

When I measure potassium it's usually around 350ml too with the salifert kit.

Excuse my ignorance, but not being pure potassium and being potassium chloride, is that an issue?

Pure potassium metal would likely catch on fire on contact with water, so potassium chloride is the way to go, and I’m sure it is what they use too, or at least by far the largest part of what they use.

To do the change over math I need to know what tank volume was being used for their calculation.

 

[ItsAName]

Makes sense. 90 Gallons is the tank volume, thank you!

 

[Randy Holmes-Farley Verified Community Expert]

OK, so we assume that 214 ml will boost 90 gallons (338.2 L) by 49 mg/l (351 mg/l to 400 mg/l) potassium.

A solution that is 77,420 mg/L potassium will have that effect. (77,420 mg/l * 0.214 L = 16,567.9 mg; put that into 338.2 L then the boost is 16,567.9 mg/338.2 L = 49 mg/L

Potassium chloride is 52.3% potassium, so to make 1 L of stock solution we add 77.4 g/0.523 = 148 grams of KCL.

Dissolve 148 grams KCl in a liter of RO/DI and it matches that need.

 

[ItsAName]

I had to walk through the math myself so I could figure it out next time Only magical number there is the 52.3%, how did you figure that out (or where did you look it up?)

What happens to the Chloride in the water, or is that not how it works?

 

[Randy Holmes-Farley Verified Community Expert]

It comes from the molecular weights (google calls it molar mass) of potassium and chloride.

Potassium chloride has a molecular weight of 74.6 grams per mole (google: mw KCl)

Potassium has a molecular weight of 39.1 g/mole (google: mw K)

So the relative amount of potassium in potassium chloride (by weight) is 39.1/74.6 = 0.524 (= 52.4%)

 

[Randy Holmes-Farley Verified Community Expert]

What happens to the Chloride in the water, or is that not how it works?

There's not really any concern with chloride additions unless you add a lot every day (say, by a lot of calcium chloride).

Seawater already has more than 19,000 ppm of chloride. The additional chloride added via KCl just gets added into this massive number. Any time you act to maintain salinity, chloride is adjusted back to normal levels (or close to it).