Strength of Sodium Nitrate Solution

[chipmunkofdoom2]

I would like to increase my nitrates. I purchased some sodium nitrate and used this calculator to create a stock solution. I used a conversion rate of 0.84g NaNO3 to 1g KNO3. I created a solution using 52g of NaNO3 and 1L of water. If I dose 1mL of this solution to 10 gallons of water, according to the calculator it will raise the nitrates by 1 ppm.

However, I have a spreadsheet and a formula that I use to calculate precise doses of supplements based on the strength of the solution. I type in tank volume, current tank concentration, desired concentration, and the strength of the solution. The formula will tell me exactly how many mL of the solution I need to dose to reach my desired concentration. In order to calculate this dose, however, I need to know the strength of the solution (in ppm nitrates) that I created.

The formula I use is below:

The variables are as follows:

TV = tank volume
TC = tank concentration
DV = dosage volume
DC = dosage concentration
C = desired concentration

I plugged in the variables from the calculator (10g [37,854 mL] tank volume, 0 ppm tank concentration, 1 mL dose volume, 1ppm desired concentration) and solved for Dc, which is the concentration of the dosing solution (in my case, the NaNO3). The formula tells me the concentration contains 37,855 ppm nitrates. When I test this by plugging in my total volume (24g) and a 1ppm increase in nitrates, the formula correctly tells me I need 2.4 mL of the solution (1 mL in 10 gallons yields a 1 ppm nitrate increase, so 2.4 mL in 24 gallons should yield a 1 ppm nitrate increase also).

Can anyone double-check my math? It appears to be correct, but I'd hate to use an incorrect assumed solution strength and crash my tank.

Thanks for the feedback!

 

[Randy Holmes-Farley]

0.84 g NaNO3 (0.61 g = 610 mg nitrate) in 1 L of water contains 610 mg/L nitrate.

2.4 mL added to 10 gallons (37854 mL) boosts nitrate by 2.4/37854 * 610 = 0.04 ppm (hardly any lol)

 

[chipmunkofdoom2]

0.84 g NaNO3 (0.61 g = 610 mg nitrate) in 1 L of water contains 610 mg/L nitrate.

2.4 mL added to 10 gallons (37854 mL) boosts nitrate by 2.4/37854 * 610 = 0.04 ppm (hardly any lol)

Sorry for the confusion Randy, I used 52g of NaNO3. Per the calculator, I needed 62g of KNO3, so I used 52g of NaNO3 (0.84 * 62g = about 52g). According to the calculator, this mix should raise nitrates in 10 gallons by 1 ppm if I dose 1 ml.

If I added 52g of NaNO3 to 1L of water, that should be about 37,761 mg/L, correct?

 

[Randy Holmes-Farley]

Sorry for the confusion Randy, I used 52g of NaNO3. Per the calculator, I needed 62g of KNO3, so I used 52g of NaNO3 (0.84 * 62g = about 52g). According to the calculator, this mix should raise nitrates in 10 gallons by 1 ppm if I dose 1 ml.

If I added 52g of NaNO3 to 1L of water, that should be about 37,761 mg/L, correct?

Yes. :)

 

[chipmunkofdoom2]

Great, thanks for the input. So calculating by weight says the solution contains 37,761 ppm of nitrates. Reversing the calculator says the solution contains about 37,850 ppm nitrates. These numbers being within 0.3% of each other makes me feel much better.

Thanks again Randy :)

EDIT: for those following along at home, it appears NaNO3 contains about 72.6% nitrates by weight. Randy, feel free to correct if this is not accurate.

 

[Oshengems]

Great post for reference!

I have a few questions...

I wanted to know how long can a batch last me? I wanted to make a stock of 4L that will last me well over 6-7 months.

Currently I made a batch using 52g of NaNO3 mixed with 2L of RoDI water to dose 16ml a day to about 80-85gallon tank to increase No3 about 1ppm a day while I figure out my tanks consumption, roughly this will last me about 125 days but can I make a bigger batch ? I’m afraid it will will go bad just wanted to make sure.

The 2nd question my No3 hovers between 0-5ppm most of my readings are 0 on salifert test kit and my Po4 skyrocketed from .04 to .57 on the Hanna Po4 tester(I was treating my tank and the product was seems to raise Po4) my questions is will increasing my No3 reduce my Po4 ?

I’m trying to reach 10ppm No3 and ~.02-04 Po4