Sodium Nitrate Dosing, math check.

[EnderG60]

Ok so Im currently dosing vodka to bring my phosphates down, hopefully allowing me to stop the use of GFO. Starting my phosphates where in the 0.4 to 1.0 range with and without GFO, while my nitrates never got over 2.5.

I started dosing vodka and Im now at Nitrates - 0, phosphates 0.05 but with GFO. Im starting to notice SPS color loss and my zoas and GSP are receding so I decided I need to dose nitrate to get the phosphates down farther and get the nitrates back up.

My system is 540 gallons, with 450g of actual water. I found this math on another thread.

NaNO3 - 84.995g/mol
NaNO3 is about 73% NO3
85g in 1L of water
85mg per 1mL of water.
85mg * .73 = 62mg of NO3
1ml in 10L of water = 6.2 mg/L or ppm

Taking that and adapting it to my system, shooting for a solution that will add 0.1 ppm nitrate per 1ml of solution when added to the tank.

450 gallons = 1700 litters
27.5 ml in 1700L = 1ppm NO3
1 gal = 3785ml
8850g in 1 gal = 1700mg per mL of solution = 1 ppm NO3 in 450 gallons
885g in 1 gal = 170mg per mL of solution = 0.1 ppm NO3 in 450 gallons

Does this look correct? And lastly, anyone know a grams to teaspoon conversion for this?

 

[bertoni]

From the set of rules of thumb:

Add about 0.52 grams of sodium nitrate per 100 gallons of water to raise the nitrate level by 1.0 ppm. That's about 1 tsp per 500-1000 gallons, very roughly.

To get to 0.1 ppm in 450 gallons (1700 liters), you'd need 170 mg of nitrate, or 232 mg of sodium nitrate. I'm a little confused about how you're making your solutions. 0.1 tsp should be a reasonable first guess. Do you have a scale that's precise down to the mg range?

 

[EnderG60]

I have not made a solution yet, thus asking for the math check. I have a scale that can do grams but not mg, which was why I was asking about a volume measurement.

Where did that rule of thumb come from? By that it looks like 1 tsp is equal to about 2.5 to 5.0 grams, which if dosed to my 450g tank should bring my nitrates up by 1.0-2.0. Is that correct?

I dont mind it being a little off, I can adjust the mix and dosing later. Im just trying to get in the ballpark to start and not accidentally dose my nitrates up to 30 in one shot.

 

[EnderG60]

Just found my scale and it looks like 1 tsp = 5.2 grams and 1 tbs = 17.6 grams, so slightly off the 1:3 ration of tsp to tbs.

Ill stick with 1 tsp = 5 grams for calculations. I just dosed 1 tsp to the tank and will test it later tonight and see what it did.

 

[bertoni]

Okay, that sounds about right for the density. I did the math for the rule of thumb a while back. I hope it's close enough. I am distrustful of density estimates, especially across the various different sodium nitrate products.

 

[EnderG60]

So I dosed 1 tsp and tested the next day and nitrates were still under 1. So I dosed 1 tsp again. The next day my Nitrates were reading around 5.0, but I was seeing nitrite as well which might have been throwing the nitrate reading off a bit, so I did a water change and will retest tonight.

Any idea why Im seeing Nitrite after dosing?

 

[bertoni]

I am not sure why the nitrite is showing up. As you suggest, the nitrite will confuse the nitrate test kit, though, because nitrate test kits (generally) work by converting nitrate into nitrite. Do any of the animals show signs of trouble?

 

[EnderG60]

Nope, no issues. I did a 20% change and retested and saw no nitrite and nitrates where at 2.

 

[Jwheld]

I have not made a solution yet, thus asking for the math check. I have a scale that can do grams but not mg, which was why I was asking about a volume measurement.

Where did that rule of thumb come from? By that it looks like 1 tsp is equal to about 2.5 to 5.0 grams, which if dosed to my 450g tank should bring my nitrates up by 1.0-2.0. Is that correct?

I dont mind it being a little off, I can adjust the mix and dosing later. Im just trying to get in the ballpark to start and not accidentally dose my nitrates up to 30 in one shot.

I did the math and got the same as bertoni. A solution of 233g NaNO3 mixed with a liter of RODI will raise your ppm by 0.1 when dosing 1mL.

You can get a cheap kitchen scale at some house hold supply stores. That's what I use.

 

[EnderG60]

After some testing and some measuring to get in the ballpark here is what I have come up with.

1 Tsp = 5 grams, will raise the nitrate in my 450g(of water) tank by about 1ppm.
1 gallon = 3785ml, add 74 Tsp(~1.5 cups, ~370 grams) and 51 ml of the solution will raise my tank nitrate by about 1ppm.

So using a 1.1 mL/min pump with this solution for 45-60 min will raise my tank nitrate about 1ppm. Obviously I will have to make some adjustments to fine tune it, but this gets me in the ballpark to get started with some round mixing units of 1.5 cups per gallon.

 

[bertoni]

Okay, that makes sense. Good luck!

 

[ColtonMeng]

Necro'ing this thread - I know, but wanted to add my $0.02 for those looking into this in the future.

To calculate ppm, and dosage of sodium nitrate -
EX.
tank gallonage 200 gallons, specific gravity of water 1.026.
Sodium nitrate is 72.952% as NO3, typical assay is 99.5 on any grade.
454 grams per pound.

calculation would be:
1 gram NaNO3 x assay material (.995) x molecular weight by % of NO3 (.72952)
divided by
weight of total system volume in grams (1.026 x 8.34 x 200gallon volume x 454 grams per pound)

take this result and multiply by 1,000,000. That is how much nitrate you will be adding (in PPM) on a per gram basis.

In this example, you would be adding .934 PPM of NO3 per gram of material added.

Adding to this for simplicity, at the same specific gravity level but a different system volume, your addition of sodium nitrate scales linearly.

100 gallon system, 1 gram of sodium nitrate - 1.86 ppm NO3
50 gallon system, 1 gram of sodium nitrate - 3.74 ppm NO3
400 gallon system, 1 gram of sodium nitrate - 0.47 ppm NO3

-C