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Hi,

I'm unable to get potassium nitrate where I live, but I have calcium nitrate on hand.

Just wondering how many grams of calcium nitrate I should add to a PPS Pro solution.

Thanks
 

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Why don't you order them online??? There are even sellers in this forrum.

Anyway, plants need potassium, more so then calcium. It's like saying I don't have fresh water, I only have salt water. How many cups of salt water should I drink a day?
 

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You can use calcium nitrate if you wish, but note that the effective dose of nitrates will be double that of potassium nitrate.

In addition, note that you will be increasing your GH by dosing calcium nitrate.
 

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Thanks! My tap water is very soft, so it wouldn't hurt to bring up the GH a bit, I think. I suppose then that adding 32.5 g (as opposed to 65 g of potassium nitrate) will give the equivalent dose of nitrate?
 

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I suppose then that adding 32.5 g (as opposed to 65 g of potassium nitrate) will give the equivalent dose of nitrate?
No. You have to account for the different molecular weights of potassium and calcium.
 

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just a heads up, cano3 will react with any SO4 in the solution. if you want i can give you a recipe which creates KNO3 by reacting CANO3 and K2SO4.
 

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just a heads up, cano3 will react with any SO4 in the solution. if you want i can give you a recipe which creates KNO3 by reacting CANO3 and K2SO4.
Simple single displacement reaction, but why would you want to waste the potassium sulfate in that way?
 

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Simple single displacement reaction, but why would you want to waste the potassium sulfate in that way?
actually nothing really goes to waste beside so4 will fall from the solution, so4 isn't needed in big amounts anyway, you will be left behind with KNO3 in the solution with whatever K+ levels you choose.
 

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actually nothing really goes to waste beside so4 will fall from the solution, so4 isn't needed in big amounts anyway, you will be left behind with KNO3 in the solution with whatever K+ levels you choose.
Well, the calcium sulfate precipitates out, as it is relatively insoluble (though compared to other calcium salts, quite soluble), so there is quite a bit of waste.

Sulfur is considered a macronutrient for plants, but in general, not much emphasis is placed on it because it is generally abundant.
 

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just a heads up, cano3 will react with any SO4 in the solution. if you want i can give you a recipe which creates KNO3 by reacting CANO3 and K2SO4.
You can list that recipe. I've never heard of doing that. Some countries allow calcium nitrate but not potassium nitrate. Besides it's just a neat thing to know even though I will probably never need it lol
 

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You can list that recipe. I've never heard of doing that. Some countries allow calcium nitrate but not potassium nitrate. Besides it's just a neat thing to know even though I will probably never need it lol
Ca(NO3)2 + K2SO4 --> 2KNO3 + CaSO4

1 mole of calcium nitrate and potassium sulfate generates 1 mole of calcium sulfate and 2 moles of potassium nitrate.

From there, it's a simple exercise to work out the masses of each required.
 

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OP is from SG, which bans KNO3 sales. Dr Mallick's (in SG)use to carry it, not sure if he still does.

Hence the idea of using Ca(NO3)2.

SG's tap is rather nice and pure, but many do not add GH and still quite well.
Adding a GH booster will not hurt.

Since you are adding Ca(NO3)2 to the water and K2SO4 to the water, why does it not also precipitate in the aquarium?
 

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Maybe it does, but the dose is so low you cannot see it.
+1 on what Diana said, sometime it takes a few days for it to complete its reaction, when you make the solution for the first time, it will start to react immediately and it will continue to react slowly for few days to week. in aquarium the reaction cannot be seen because reaction is slow and precipitate cannot be seen by naked eyes due to bigger volume of the water.

You can list that recipe. I've never heard of doing that. Some countries allow calcium nitrate but not potassium nitrate. Besides it's just a neat thing to know even though I will probably never need it lol
Calcium nitrate 10 gram
K2SO4 30 Gram

i have used this with great success so far, the reaction will precipitate out the SO4 and the solution become Highly concentrated KNO3 with high K+, the recipe is just to give you an example and you can increase or decrease the amount as long as the ratio stays about the same. however, this recipe might not be causing the 100% reaction because i am sure you could cause better reaction by increasing or decreasing those two chemicals, but so far it has worked for me without any issue.
 

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Since you are adding Ca(NO3)2 to the water and K2SO4 to the water, why does it not also precipitate in the aquarium?
Maybe it does, but the dose is so low you cannot see it.
+1 on what Diana said, sometime it takes a few days for it to complete its reaction, when you make the solution for the first time, it will start to react immediately and it will continue to react slowly for few days to week. in aquarium the reaction cannot be seen because reaction is slow and precipitate cannot be seen by naked eyes due to bigger volume of the water.
As mentioned previously, calcium sulfate, while being relatively insoluble, is still soluble (Ksp is only on the order of -5). In the large amount of water that aquariums typically are, there is no problem of trying to dissolve all of it. In addition, as it happens in such a large volume, if it does precipitate, it would appear as a slight haze, and probably not visible.

I would not say that it would take several days to complete, however. Single displacement reactions are usually rather quick.

Calcium nitrate 10 gram
K2SO4 30 Gram

i have used this with great success so far, the reaction will precipitate out the SO4 and the solution become Highly concentrated KNO3 with high K+, the recipe is just to give you an example and you can increase or decrease the amount as long as the ratio stays about the same. however, this recipe might not be causing the 100% reaction because i am sure you could cause better reaction by increasing or decreasing those two chemicals, but so far it has worked for me without any issue.
Ca(NO3)2 + K2SO4 --> 2KNO3 + CaSO4

1 mole of calcium nitrate and potassium sulfate generates 1 mole of calcium sulfate and 2 moles of potassium nitrate.
The above ratio will work, but you have a large excess (almost 3 times) of potassium sulfate. You would have a solution rich in potassium, nitrate, and relatively rich in sulfates.

Do note that the reaction does not precipitate out "sulfates," it precipitates out calcium sulfate.
 

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As mentioned previously, calcium sulfate, while being relatively insoluble, is still soluble (Ksp is only on the order of -5). In the large amount of water that aquariums typically are, there is no problem of trying to dissolve all of it. In addition, as it happens in such a large volume, if it does precipitate, it would appear as a slight haze, and probably not visible.

I would not say that it would take several days to complete, however. Single displacement reactions are usually rather quick.




The above ratio will work, but you have a large excess (almost 3 times) of potassium sulfate. You would have a solution rich in potassium, nitrate, and relatively rich in sulfates.

Do note that the reaction does not precipitate out "sulfates," it precipitates out calcium sulfate.
yes that is correct, it form Ca sulfate and it does take a few days for the reaction to complete in the solution, i have seen it continue to react for few days because i would filter out most of the Ca sulfate from the solution, at some point it would finally stop to react further. the CaSO4 in the solution will not mix with the solution, it will just sit there on the bottom, when you add the solution to the aquarium, you are really only adding K+ and NO3, unless you shake the solution which might add some Caso4 to the tank otherwise so4 sits on the bottom.

Do note that the reaction does not precipitate out "sulfates," it precipitates out calcium sulfate.
yeh but isn't that formed by reaction of SO4 and Ca in the solution from CAno3 and K2so4, what you are left with is KNO3 here and rest of the Caso4 sitting at the bottom in powder/paste form which can be filtered out, the solution is only KNO3 and no SO4 in the liquid form.
 
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