Reef-safe sodium nitrate ?

[Yanir34]

Hello everyone , i recived today new bottele of sodium nitrate , but i noticed something strange written on the label of the bottle, that there are also various metals in very low concentrations. Is this normal? Is it safe to use in the reef ?

 

[Dan_P]

Hello everyone , i recived today new bottele of sodium nitrate , but i noticed something strange written on the label of the bottle, that there are also various metals in very low concentrations. Is this normal? Is it safe to use in the reef ?

Yes and Yes.

When you do the math, you will see that the added ppm of these elements will be very low. If you are still nervous, you could buy food grade sodium nitrate. It will be a bit purer.

 

[Randy Holmes-Farley]

I’d use it.

 

[Yanir34]

Thanks guys , i started the dosing today

 

[Yanir34]

Some supdates - its now 5 days of doaing sodium nitrate and pottasium phosphate .
No3 is at 2 ppm now.
Po4 is at 0.03 now.

My alk levels was stable before the doaing : 8.0 to 8.4
Yesterday i noticed that my alk got up to 9.6 dkh , and that is not good.
I'm assuming that its related to the dosing of no3 , po4.
Just dont understand why its happend
.

 

[homer1475]

Neither of those chemicals(sodium nitrate, potassium phosphate) will contribute to your ALK increase. Look elsewhere for those issues.

 

[Yanir34]

Neither of those chemicals(sodium nitrate, potassium phosphate) will contribute to your ALK increase. Look elsewhere for those issues.

I simply replaced new reagent. Because the old one finished.
With the old reagent the results was 8.2 dkh.
With the new reagent its 9.6 (!!)
Im using hanna HI772 digital checker

 

[homer1475]

Could be a reagent issue?

After years of using the hanna, I always test the last bit in the bottle, against the new reagent bottle. Sometimes they are the same, sometimes they are not, but they are usually close. Many stories of high reading when using the last bit of reagent.

Just out of curiosity, do you only use the stated 25 tests, or try to use the last bit in the bottle?

 

[Yanir34]

Im using the last bit of the bottle.
One thing is for sure - i will hook up my KH director soon as possible .
I cant afford any mistakes of that kind.

 

[homer1475]

Many years ago I started marking my bottles, and only using the stated 25 tests(yes there is always a little bit more), but my tests are way more consistent bottle to bottle now. Read a while ago from a hanna rep on here that they add a little bit more just for spillage, not exactly measuring, etc. Only use the stated 25 tests.

There is a huge thread down here in the chem section somewhere about refrigerating the bottles to get more consistent results also. Seems to help quite a few.

 

[Randy Holmes-Farley]

I simply replaced new reagent. Because the old one finished.
With the old reagent the results was 8.2 dkh.
With the new reagent its 9.6 (!!)
Im using hanna HI772 digital checker

If you dose and consume 50 ppm of nitrate, alk will rise by 2.3 dKH. Not sure if that explains your issues.

Any other dosing?

 

[Yanir34]

Only Alk, Cal, Mag , no3 ,po4

 

[billyocean]

Keep your hanna regent in the fridge and and shake before each use..it will stay accurate. They should start putting it on the bottle because it works.

 

[Yanir34]

If you dose and consume 50 ppm of nitrate, alk will rise by 2.3 dKH. Not sure if that explains your issues.

Any other dosing?

That explain it vwry well....why is that ? Why dosing nitrate cause such huge spike at the Alk ?

 

[Yanir34]

Keep your hanna regent in the fridge and and shake before each use..it will stay accurate. They should start putting it on the bottle because it works.

I didnt knew that...

 

[Yanir34]

Simply put in the fridge...?

 

[billyocean]

Simply put in the fridge...?

Yes. It gives inaccurate readings after a while if not refrigerated. I always shake before each use too...dunno if it helps.

 

[shootingstar_reef]

Use the tropic marin alkalinity test :)

 

[Randy Holmes-Farley]

That explain it vwry well....why is that ? Why dosing nitrate cause such huge spike at the Alk ?

Each nitrate consumed adds one unit of alkalinity. This has more:

http://reefkeeping.com/issues/2004-12/rhf/index.htm

Alkalinity Decline in the Nitrogen Cycle

One of the best known chemical cycles in aquaria is the nitrogen cycle. In it, ammonia excreted by fish and other organisms is converted into nitrate. This conversion produces acid, H+ (or uses alkalinity depending on how one chooses to look at it), as shown in equation 1:

(1) NH3 + 2O2 --> NO3- + H+ + H2O
For each ammonia molecule converted into nitrate, one hydrogen ion (H+) is produced. If nitrate is allowed to accumulate to 50 ppm, the addition of this acid will deplete 0.8 meq/L (2.3 dKH) of alkalinity.

However, the news is not all bad. When this nitrate proceeds further along the nitrogen cycle, depleted alkalinity is returned in exactly the amount lost. For example, if the nitrate is allowed to be converted into N2 in a sand bed, one of the products is bicarbonate, as shown in equation 2 (below) for the breakdown of glucose and nitrate under typical anoxic conditions as might happen in a deep sand bed:

(2) 4NO3- + 5/6 C6H12O6 (glucose) + 4H2O --> 2 N2 + 7H2O + 4HCO3- + CO2
In equation 2 we see that exactly one bicarbonate ion is produced for each nitrate ion consumed. Consequently, the alkalinity gain is 0.8 meq/L (2.3 dKH) for every 50 ppm of nitrate consumed.

Likewise, equation 3 (below) shows the uptake of nitrate and CO2 into macroalgae to form typical organic molecules:

(3) 122 CO2 + 122 H2O + 16 NO3- --> C106H260O106N16 + 138 O2 + 16 HCO3-
Again, one bicarbonate ion is produced for each nitrate ion consumed.

It turns out that as long as the nitrate concentration is stable, regardless of its actual value, there is no ongoing net depletion of alkalinity. Of course, alkalinity was depleted to reach that value, but once it stabilizes, there is no continuing alkalinity depletion because the export processes described above are exactly balancing the depletion from nitrification (the conversion of ammonia to nitrate).

There are, however, circumstances where the alkalinity is lost in the conversion of ammonia to nitrate, and is never returned. The most likely scenario to be important in reef aquaria is when nitrate is removed through water changes. In that case, each water change takes out some nitrate, and if the system produces nitrate to get back to some stable level, the alkalinity again becomes depleted.

If, for example, nitrate averages 50 ppm at each water change, then over the course of a year with 10 water changes of 20% each, the alkalinity will be depleted by 1.6 meq/L (4.5 dKH) over the course of that entire time period. This process is one of the primary reasons that fish-only aquaria that often export nitrate in water changes need occasional buffer additions to replace that depleted alkalinity.
While the magnitude of the depletion described in the paragraph above is fairly easy to understand, it also can be converted into units that clarify the imbalance. The impact of alkalinity depletion on the calcium and alkalinity demand balance depends, of course, on the amount of calcium and alkalinity added (and consumed) over the course of that same year.

For a typical reef aquarium (assuming a daily addition of saturated limewater equal to 2% of the tank's volume), the amount of alkalinity added during the course of a year is 297.8 meq/L. Likewise, the amount of calcium added is 5,957 ppm Ca++, given the ratio of 1 meq/L of alkalinity for every 20 ppm of calcium that has been discussed above. If that 1.6 meq/L of alkalinity is added to create a larger demand of 299.4 meq/L over the course of a year, the new ratio for the total demand becomes 19.90 ppm Ca++ per 1 meq/L of alkalinity. Consequently, while this effect of nitrate production on alkalinity is enough to be noticed over the course of a year, it is substantially smaller than the other effects discussed in this article, and is unimportant for aquaria that maintain low nitrate levels.