Potassium Chloride KCl - 74.55

[Ponraj A]

@Randy Holmes-Farley

Hi Mr.Randy,This is Ponraj.

I am trying the above Potassium Chloride (74.55 molar mass) for supplementing potassium. I am calculating as below, please correct me if i am wrong.

KCl 74.55 contains Cl - 47.56% ; K - 52.44%
Tank volume - 575 ltrs
Can raise max.20ppm per day

1. Mixing 1gm of KCl in 1000ml of water - K - 524.4ppm
2. divide 524.4ppm / 20ppm = 26.2
3. then divide tank water 575/26.2 = 21.9ml will raise 20ppm potassium in my tank

Please suggest.

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley

Hi Mr.Randy,This is Ponraj.

I am trying the above Potassium Chloride (74.55 molar mass) for supplementing potassium. I am calculating as below, please correct me if i am wrong.

KCl 74.55 contains Cl - 47.56% ; K - 52.44%
Tank volume - 575 ltrs
Can raise max.20ppm per day

1. Mixing 1gm of KCl in 1000ml of water - K - 524.4ppm
2. divide 524.4ppm / 20ppm = 26.2
3. then divide tank water 575/26.2 = 21.9ml will raise 20ppm potassium in my tank

Please suggest.

No.

Step 1 is correct, as far as it goes. There is 523 mg of potassium in that 1 liter of water.

If you added that entire solution containing 523 mg of potassium to your aquarium with 575 L, the potassium concentration will only rise by 523 mg/575 L = 1 mg/L (= ppm).

What rise do you want in the aquarium?

(you need to multiply in step 3, not divide)

 

[Ponraj A]

No.

Step 1 is correct, as far as it goes. There is 523 mg of potassium in that 1 liter of water.

If you added that entire solution containing 523 mg of potassium to your aquarium with 575 L, the potassium concentration will only rise by 523 mg/575 L = 1 mg/L (= ppm).

What rise do you want in the aquarium?

(you need to multiply in step 3, not divide)

ooh, So now you know , how poor i am in chemistry and calculation. I want to raise 20ppm of potassium to my tank. Please advise.

 

[Randy Holmes-Farley Verified Community Expert]

ooh, So now you know , how poor i am in chemistry and calculation. I want to raise 20ppm of potassium to my tank. Please advise.

Dissolve 22 grams of KCl (11.5 grams of K+) in any amount of water and add it to your aquarium to boost the potassium by 11,500 mg/575 L = 20 mg/L (20 ppm).

 

[Ponraj A]

Dissolve 22 grams of KCl (11.5 grams of K+) in any amount of water and add it to your aquarium to boost the potassium by 11,500 mg/575 L = 20 mg/L (20 ppm).

Thank you so much for your time and once again thanks for solving this.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you so much for your time and once again thanks for solving this.

You're very welcome.

Happy Reefing.

 

[TheEngineer]

If I can please tag along here...

I need to raise my K by 160ppm (currently at 240ppm via Salifert potassium kit and Triton test). I'm assuming I shouldn't raise it all at once, is there a safe amount to increase by daily?

I'm using the Now Potassium Chloride powder which is 325mg per 1/8 teaspoon....

mg needed = 190 liters * 160 ppm = 30,400 mg

tsp needed = 30,400 mg / (365 mg/.125 tsp) = 10.4 tsp

Does that math check out?

 

[Randy Holmes-Farley Verified Community Expert]

I'm using the Now Potassium Chloride powder which is 325mg per 1/8 teaspoon....

How did you arrive at that? Is that potassium only? or KCl?

Assuming it is a correct evaluation of the potassium in 1/8 teaspoon, then I get 11.7 teaspoons from your math.

I'd spread it out over a few days. It's a big boost.

 

[TheEngineer]

How did you arrive at that? Is that potassium only? or KCl?

Assuming it is a correct evaluation of the potassium in 1/8 teaspoon, then I get 11.7 teaspoons from your math.

I'd spread it out over a few days. It's a big boost.

The side of the bottle Serving size is 1/8 tsp with 365mg Potassium from Potassium chloride per serving.

You get 11.7? Err...?? Let me do this step by step, where am I going wrong....

190 liters * 160 ppm = 30,400 mg

365 mg / .125 tsp = 2920 mg/tsp

30,400 mg / 2920 mg/tsp = 10.41 tsp

Did I go wrong somewhere?

 

[Ponraj A]

@Randy Holmes-Farley
I have learned something from Mr.Randy for the calculation of Chemicals presentation (I am not a chemist and very poor in that too) The below calculation works for me. If you need I am happy to share this excel file if you want to by email as this can't be uploaded in R2R.
Please find below a screen shot of the same. You have to enter the result of test and can find how much ml need for my tank.

 

[Randy Holmes-Farley Verified Community Expert]

The side of the bottle Serving size is 1/8 tsp with 365mg Potassium from Potassium chloride per serving.

OK, perfect.

You get 11.7? Err...?? Let me do this step by step, where am I going wrong....

190 liters * 160 ppm = 30,400 mg

365 mg / .125 tsp = 2920 mg/tsp

30,400 mg / 2920 mg/tsp = 10.41 tsp

Did I go wrong somewhere?

I see the problem. You said 325 mg per 1/8th teaspoon in the first statement, and I did the math off of that. In your write up you wrote 356 mg/1/8th teaspoon, and you did the math off that. I'm not sure which matches the bottle label.

 

[TheEngineer]

OK, perfect.




I see the problem. You said 325 mg per 1/8th teaspoon in the first statement, and I did the math off of that. In your write up you wrote 356 mg/1/8th teaspoon, and you did the math off that. I'm not sure which matches the bottle label.

Fat fingered that apparently It is 365.

I did what should have been a 10 ppm bump as a test dose yesterday, 0.5 tsp. I tested again this morning and got an 80 ppm increase... Could have been testing error. I'm going to do it again when I get home from work and recheck it before I dose again.