Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

[srozell]

After discovering that calcium carbonate only precipitates in alkaline tanks, I've been looking at different methods of getting calcium into an obviously calcium deficient tank. Maybe some of you have already crossed this hurdle, and if so I would like to know how.

At any rate, I picked up a bag of 5Ca(NO3)2.NH4NO3.10H2O and have been playing with it with no detrimental effects in a heavily planted tank. Before I increase my dosing regime however I would like some feedback on any negative side effects I might encounter.

I figure the H20 part can't hurt in an aquarium. The understand the ammonia is about 1% of the compound, and it should be sucked up by the plants in no time, along with the nitrogen. And the Calcium, well it's water soluble in this form so it SHOULD solve my problem. Right?

Thoughts? Anyone?

 

[Laith]

Re: Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

I'd be wary of adding ammonia to a planted tank. It can trigger algae, though perhaps not in the low concentrations you're speaking of.

Why not just add CaCl2? dissolves very easily and is easy to find.

 

[fosteder]

Re: Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

I use CaCl2. It works great. It still takes a little time to dissolve, but it is a whole lot better than calcium carbonate....

 

[andrewmcleod]

Re: Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

After discovering that calcium carbonate only precipitates in alkaline tanks

Well it's not really that simple. If you have added, say, calcium chloride and sodium carbonate, then you will have calcium ions, chloride ions, sodium ions and carbonate ions all separated from each other, just as if you'd gotten calcuim carbonate and sodium chloride to dissolve.
The problem with calcium carbonate is that it is fairly insoluble, so if you put it in just a little water it won't want to dissolve. If you chuck a little in a whole tank full of water, however, it will dissolve - but it might still take some time.
The fact that you can have non-zero KH (99% carbonate) and non-zero calcium levels at once means that the 'calcium carbonate precipitates out' thing is not really true. Look at sea water! Huge amounts of calcium and carbonates, but it only precipitates under unusual circumstances in the sea (to make limestone etc).

 

[happychem]

Re: Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

For CaCO3 to be actively precipitating you'd need to have very high pH and to be adding large quantities of CaCO3 yourself. If water comes from your taps with a high alkalinity, then you probably don't need to supplement Ca. If you do, CaCl2 is a pretty good route, especially since it doesn't affect alkalinity.

If you do have a solubility problem, try lowering the temperature a bit if you keep your water warm. CaCO3 solubility decreases with increasing temperatures, this is why some boil water to decrease hardness. This is also an issue in the oceans, where temp. decreases with depth you reach a point called the lysocline where CaCO3 dissolves faster than it forms, among the reasons why it is very difficult to find deep water corals.

If you're adding CO2, it's not likely an issue. CO2 reacts with CO3 and water to form bicarbonate, shifting the CaCO3 equilibrium towards dissolving more.

 

[Tom Barr]

Re: Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

I used to do water treatment for drinking water and we use lime to raise the pH to about 10.1, this preciptates out the CaCO3.
See Mono lake tufa.(Mono lake's pH is about 10.1)

Organisms do the same thing for their CaCO3 shells to preciptate out the CaCO3, they pump OH's out slowly to form the shells.

I'd just use plain old Ca(NO3)2.
But the small amount of NH4 likely will not hurt.....either.

Regards,
Tom Barr

 

[srozell]

Re: Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

Thank you.

Ca(NO3)2 was available, but more expensive. I didn't expect a problem with the extra NH4 based on how my tanks are planted and dosed.

Thanks for the feedback.

Spencer

 

[Tom Barr]

Re: Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

Depending on the cost difference, I think that may be the main thing.
Lots of Ca in the other though.

regards,
Tom Barr

 

[srozell]

Re: Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

Good to know.

The straight Ca(NO3) was twice as expensive.

 

[Greg Watson]

Re: Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

Good to know.

The straight Ca(NO3) was twice as expensive.

It shouldn't be ... what did they want for it?

Greg

 

[srozell]

Re: Calcium Nitrate w/ Ammonia: 5Ca(NO3)2.NH4NO3.10H2O

It shouldn't be ... what did they want for it?

Greg

About $.50 CAD / lb