raising potassium with KCL

[CoralWealth]

Hello!

So my SPS dominant tank has low potassium because I was lazy on water changes but I want to make sure I am keeping it steady when I do not do water changes. My salinity is at 1.026

Right now it is around 250. ATI ICP tested 230 and my salifert test kit tested 250 so it has to be somewhere around there.

I got some KCL from amazon and I want to slowly raise it to around 400.

My system is around 250 gallons.

Would it be okay to raise K by around 50 per day? If so, what is the mix I make? I am having a hard time figuring this out, clearly I am not a chemist haha. I just want to make sure I do not dose too much.

Would it be like 100 grams of KCL per 1L of fresh water to add to my 300 gallons over a day to raise it around 50 or am I doing the math wrong?

 

[JimWelsh]

In order to solve this kind of problem (VERY common dosing question), you need to know the molecular weight of the substance (KCl MW = 74.55) and the atomic weight of the element of interest (K = 39.1). From that, you can determine that KCl is 39.1 / 74.55 = 52.45 % potassium. Solubility of the substance is sometimes an issue, but not so much with KCl, since it is quite soluble. Using your example, 100 grams of KCl dissolved in (however much) water, when added to 300 gallons of saltwater will raise potassium by 100 grams * 54.45% / (300 * 3.87854) = 46.2 mg / L.

 

[CoralWealth]

In order to solve this kind of problem (VERY common dosing question), you need to know the molecular weight of the substance (KCl MW = 74.55) and the atomic weight of the element of interest (K = 39.1). From that, you can determine that KCl is 39.1 / 74.55 = 52.45 % potassium. Solubility of the substance is sometimes an issue, but not so much with KCl, since it is quite soluble. Using your example, 100 grams of KCl dissolved in (however much) water, when added to 300 gallons of saltwater will raise potassium by 100 grams * 54.45% / (300 * 3.87854) = 46.2 mg / L.

Thank you!!

Awesome! I greatly appreciate you walking it out for me. So I was pretty close that 100gram of KCL will raise my 300 gallons around 50, which you made it much more exact and it will raise it by 46.2

 

[CoralWealth]

So I am still wondering how fast I can raise my potassium? Can I raise it to 400 in a day or only like 50 a day?

 

[CoralWealth]

anybody?

 

[Randy Holmes-Farley Verified Community Expert]

230 sounds suspiciously low to be real, but if you think it real, I'd raise it slowly (at least a week to do so).

 

[CoralWealth]

230 sounds suspiciously low to be real, but if you think it real, I'd raise it slowly (at least a week to do so).

It was 100% that low. I haven’t done a water change in 3 months and I have SPS dominant tank. ATI icp and salifert potassium test confirmed it. When I raised it 50 the test kit confirmed it exactly too.

 

[Randy Holmes-Farley Verified Community Expert]

It was 100% that low. I haven’t done a water change in 3 months and I have SPS dominant tank. ATI icp and salifert potassium test confirmed it. When I raised it 50 the test kit confirmed it exactly too.

I'm not going to claim otherwise, but if you are certain the potassium is low I'd raise it.