2 part dosing Ca, holding Alk

[t5Nitro]

Can I apply the dilution calculations to NaNO3? I'm getting greatly different numbers from the online planted tank calculator and on paper. FW NaNO3 = 85mg/mmol. Valence 1.

113g NaNO3 = 113,000mg / 85mg/mmol = 1329.4mmol x valence of 1 = 1329.4 mEq.

Using the planted tank calculator of potassium nitrate, 140g should be ~113g NaNO3 (the whole loudwolf NaNO3 bottle volume by weight). I take 140 x 0.81 to get NaNO3 strength (found somewhere on this forum). It tells me 140g of potassium nitrate or my 113g sodium nitrate in 300mL of water gives me a stock solution that would raise my 284L by 1ppm in 1 mL.

1329.4mEq / 0.3L = 4431 ppm stock.

1 ppm = 4431 ppm x Y mL / 284,000mL; this tells me I should dose 64mL to raise my tank 1ppm as opposed to the planted calculator saying 1mL is about 1ppm.

 

[Randy Holmes-Farley Verified Community Expert]

The calculator doesn't lie. lol

Sodium nitrate is 73% nitrate by weight.

113 grams of sodium nitrate contains 82.4 grams of nitrate.

Dissolve that in 300 mL, then you will roughly (ignoring density) have about 82.4 g/300 ml = 0.27 g or 270 mg/mL.

Assuming you correctly determined you tank volume to be 284,000 mL (284 L), then 1 mL that contains 270 mg will raise nitrate by 270 mg/mL x 1 mL/284 L, which is a tad under 1 ppm.

I think your error is here:

"1329.4mEq / 0.3L = 4431 ppm stock. "

You went from milliequivalents to ppm without accounting for the weight of the nitrate.

 

[t5Nitro]

If I were to use the same calculation pathway as with the alkalinity dosing I come up with the same number after accounting for nitrates weight. Too confused.

113g na NO3 contains about 82.4g no3 by weight.

If 82400mg no3 / 62 mg/mmol x valence 1 I get the same 1329 mEq into the same 0.3L volume and the same ppm stock.

Sorry, not trying to give you a hard time. I may just pester our pharmacists at work sometime.

I mixed up the solution based on the planted tank site calculator just before you replied. Figured you can't go wrong with that.

 

[Randy Holmes-Farley Verified Community Expert]

If I were to use the same calculation pathway as with the alkalinity dosing I come up with the same number after accounting for nitrates weight. Too confused.

113g na NO3 contains about 82.4g no3 by weight.

If 82400mg no3 / 62 mg/mmol x valence 1 I get the same 1329 mEq into the same 0.3L volume and the same ppm stock.

Sorry, not trying to give you a hard time. I may just pester our pharmacists at work sometime.

I mixed up the solution based on the planted tank site calculator just before you replied. Figured you can't go wrong with that.

I don't understand what you are saying now. You still think your calculation was right? I pointed out exactly why it is wrong.

ppm is mg/kg, which is about the same as mg/L.

You calculated millimoles (milliequivalents) per liter dosed, not mg/L. Since 1 meq/L nitrate = 62 mg/L, that is the reason yours was off.