Formula needed for Potassium Dosing

[skuller]

Hello Guys:

I am new as a user here on R2R, however I must say I am not new in reading the forum, been reading R2R a lot of time ago, and now I decided to register in the forum to post.

So, I am looking for a formula to dose Potassium to my tank, I just purchased the KCl, here are also the pictures of it.

My tank is: 180 Liters NET Water (aprox 47 Gal).
My K value is at: 340ppm (tested with Salifert).
My goal is to have it at 400 ppm.
Drops: 1 drop at a time should rise K in 1ppm in my 180L,

Dosage daily: I want to dose 5 drops daily to increment the K in 5ppm every day.

May be someone can help with this formula? Or if you have a basic formula I can do the math and modify it to meet these daily dosage.

Thank you guys in advance.

 

[skuller]

I found this formula on the forum:

You could make a stock solution of any strength. I personally would shoot for something generic, like 1 ml per 10 gallons gives a 1 ppm increase in K. To do this, mix about 72.187g of KCl in 1 liter of water. KCl is about 52.44% K by weight. So, 72.187 g in 1 liter of water will give you about 37.854 g/L of K, which is about 37,854 ppm. 1 mL of this solution should raise 10g of tank water by 1 ppm. To make one gallon of this solution, add 280g of the KCl to one gallon of water.

So, if my math are ok is like this:
Dissolve 72.187 grms of KCl in 1 liter of rodi water, 1 mL of this solution will rise the K in 1 ppm, in a reef tank of 37.8541 Liters
Dissolve 343,25 grms of KCl in 1 liter of rodi water, 1 mL of this solution will rise the K in 1ppm in a reef tank of 180 Liters

but I only need 60 ppm...so I will be using only 60 mL of this solution, if I need 343,24 grms for 1000 mL and have 1000 ppm in this solution then:
1000/60 = 16.66 factor (because I need only the 16.66th part on that solution)
so.... 343.25 / 16.66 = 20.59 grms

I need 20.59 grms of KCl to rise my aquarium of 180 Liters in 60 ppm.
Now I can dissolve that amount in whatever solution of rodi water I need to meet the 1ppm drop by drop..

20 drops = 1 mL
and I will do this solution in 25ml
then I have 500 drops which are equal to 60ppm
60ppm / 500 = 0.12 ppm

So, each drop will have the power to rise K by 0.12 ppm, in this way I can dose 8 drops at morning and 8 drops at the afternoon and will be incrementing the K in 2 ppm by day, and it will take 30 days to get to 400ppm, or I can dose double and get there in 15 days.


mmmm, I think I better go for a coffee..

 

[Daniel@R2R Verified Admin]

This is something I've never tried. #reefsquad

 

[skuller]

I made it simple, mixed 61 grms of that KCl in 200 mL of rodi water.
1mL of that solution will rise my K in 1 ppm in my 180L tank, I hope the maths are OK?


The red colors in my monti caps are really faded, and my Seriatopora Caliendrums are all horrible, no PE and bleached in some cases...can that be because of this K value of 340ppm?

 

[vetteguy53081]

I add 1 m/l potassium by Brightwell every other day for my SPS

 

[John Hanna]

@skuller Just confirming your maths is correct. 20.59g needed for a 60ppm K increase within 180L system. Good to see an American site using mL and Litres as it should be

 

[skuller]

Thank you John!

 

[skuller]

Thank you John!

 

[John Hanna]

No Problem mate. Just be aware that drop size varies with the device that distributes it so you may want to calibrate it first if you're really pushing accuracy. Alternatively use a higher volume to make it less prone to variation may be the easier route to follow - you could use a graduated syringe for example.

 

[skuller]

Thank you John, I did the dosage with a 1mL syringe, but it seems I calculated more than needed and when I started dosing the K went up a little bit faster than expected, may be I am having less NET water volume than I thought. It is impossible to know exactly how much NET water I have on the system.


However.. my dosage is now adjusted to what I need and the corals did not reacted bad on the dosage.
Now that I am almost on the target number (current 380ppm) will try to find the weekly consumption of Potassium for weekly dosage.

 

[Randy Holmes-Farley Verified Community Expert]

I add 1 m/l potassium by Brightwell every other day for my SPS

Do you ever measure potassium?

 

[Randy Holmes-Farley Verified Community Expert]

Now that I am almost on the target number (current 380ppm) will try to find the weekly consumption of Potassium for weekly dosage.

There may not be any net consumption (my tank had none), but its a good thing to determine.

 

[skuller]

Do you ever measure potassium?

Hi Randy, yes, I was having issues with all my Seriatoporas Caliendrum and with my monti Caps, so I was adviced by the guys at zeovit forum to measure potassium, the result of a test with Salifert Potassium test kit was only 340ppm of K.
I started dosing this solution with 2-5 mL a day, after a few days I reached 380ppm, now I am dosing 1 ppm a day to reach 390-400ppm of potassium.

After 5 days of dosing potassium my seriatoporas caliendrium are all showing better polyp extension and the ones at the top seems to be growing with new tips (this is barely noticeable..but I can see it)..they were STNing..so I cannot be more happy with this, my monti caps started to develop some really good red colors.

I am running full Zeovit since 4 months ago, but before that I was running my system with only 5% WC every week, running a powerful scrubber and my tank fully stocked with SPS and only 3 very small fishes, I believe that was the thing that made my K to get lower and lower, and I never tested for K.