Sodium Nitrate dosing gone wrong

[MarsReefer]

Hoping someone can help me understand where I went wrong so I don’t do this again. my nitrates were pretty low (around 1ppm) compared to my phosphates (0.15) so I wanted to dose slowly to bring my nitrates up to 10 ppm.

I mixed up a batch of sodium nitrate solution based on this calculator for potassium nitrate and figured I’d knock off 10% since sodium and potassium nitrate are slightly different. I used this calculator below.

Based on what it told me I added 7 teaspoons of sodium nitrate to 400 ml of water and then dosed 10 ml to my 160 gallon (total volume) tank.

I expected to get about 1.5 ppm increase in my tank after 24 hours. Instead it is reading off the scale at 75 ppm now. Based on the color of the solution my guess is that I’m over 100 ppm.

What did I do wrong? Is this calculator just bad?

Edit: turns out I accidentally used my nitrate dosing syringe to test my nitrates. No issue with the dose I was using.

 

[KrisReef]

Molar mass of potasium is 101.1 g/mole
Sodium is 84.9

Otherwise, I don't know what went wrong, Randy can probably trouble shoot this.
@Randy Holmes-Farley

 

[TokenReefer]

What test kit are you using?

 

[KrisReef]

Also, when ever I start adding home mixed stuff I try a few drops and remeasure to see if I am on the right track or on the highway in that AC/CD song. :smiling-face-with-sunglasses:

 

[MarsReefer]

What test kit are you using?

using the hanna test kit. Same batch of reagent I’ve been measuring 1-2 ppm with for the last 4 weeks, so reasonably sure it isn’t the reagent packets.

 

[The_Paradox]

using the hanna test kit. Same batch of reagent I’ve been measuring 1-2 ppm with for the last 4 weeks, so reasonably sure it isn’t the reagent packets.

Pretty sure something is effecting reagent. I don’t see any way 10ml raised 160 gallons of water to over 100ppm.

 

[TokenReefer]

using the hanna test kit. Same batch of reagent I’ve been measuring 1-2 ppm with for the last 4 weeks, so reasonably sure it isn’t the reagent packets.

Ok. I assume the HR since you read up to 75 ppm. Very curious. Following.

 

[MarsReefer]

So after some replies here at least hinting I’m not totally crazy I went back and looked over everything.

Turns out I used my nitrate dosing syringe to test me nitrates instead of my testing syringe. Used the correct one and got 4 ppm as expected.

Lesson learned: label syringes better.

 

[Randy Holmes-Farley Verified Community Expert]

Glad all is well. :)

 

[BigFig]

You are not alone, my friend. I’ve done the same thing.