Potassium carbonate - Potas

[Cor]

My supply of K₂CO₃ has run out.
Could I also use the raising/leavening agent Potash, which you can buy at any bread shop, or is this a slightly different composition?

 

[Zeus.]

Potash has been used as a cheap fertilizer for many years in many countries, its composition varies slightly from where its been mined. Many commercial fertilisers use it in agriculture and our hobby.

The Potash used for baking is mainly Potassium Bicarbonate plus there is also Potassium Nitrate used for curing meat. So you just need to check your getting the Bicarbonate for cooking - then just check the mass needed for the same change in K and kH to suit your tank

I think you should be fine I'm sure @dw1305 and @X3NiTH will chip in as well

 

[dw1305]

Hi all,

Could I also use the raising/leavening agent Potash, which you can buy at any bread shop, or is this a slightly different composition?

the Potash used for baking is mainly Potassium Bicarbonate

Yes, I'd guess it would be potassium bicarbonate (KHCO3), or a mix with potassium carbonate (K2CO3), rather than potassium carbonate on its own. It might also contain an acid, possibly <"cream of tartar"> (KC4H5O6). It should say on the ingredients.

Other options for compounds it might contain are are sodium bicarbonate (NaHCO3), <"monocalcium phosphate"> (Ca(H2PO4)2) and <"sodium aluminium sulphate"> (NaAl(SO4)2.12H2O).

Because of the <"unknown unknowns">, what is your tap water like? Until you get some more potassium bicarbonate came I might be tempted to try <"a dash of tap water">.

cheers Darrel

 

[_Maq_]

My supply of K₂CO₃ has run out.

What for are you using it?

 

[Cor]

What for are you using it?

I use it forthe potassium levels

 

[Cor]

what is your tap water like?

Gonna use RO water, so the K₂CO₃ for potassium and also to raise the Dhk levels a bit

 

[_Maq_]

for potassium and also to raise the Dhk

For raising alkalinity I'd suggest CaCO3. For potassium fertilizers, there are better choices: KNO3, K2SO4, KCl.

 

[dw1305]

Hi all,

I use it forthe potassium levels .......... Gonna use RO water, so the K₂CO₃ for potassium and also to raise the Dhk levels a bit

That makes sense, but I'd just use another potassium (K) salt, they <"are all soluble">. If you can't get <"potassium nitrate"> (KNO3), dipotassium phosphate (K2HPO4) would give you a useful anion as well.

For alkalinity <"carbonate hardness (dKH)"> I'd honestly just use some tap water, so don't need very much and it also will supply some calcium (Ca) as well.*

*Edit what @_Maq_ says.

cheers Darrel

 

[Cor]

For potassium fertilizers, there are better choices: KNO3, K2SO4, KCl.

Hi all,

That makes sense, but I'd just use another potassium (K) salt, they <"are all soluble">. If you can't get <"potassium nitrate"> (KNO3), dipotassium phosphate (K2HPO4) would give you a useful anion as well.

For alkalinity <"carbonate hardness (dKH)"> I'd honestly just use some tap water, so don't need very much and it also will supply some calcium (Ca) as well.*

*Edit what @_Maq_ says.

cheers Darrel

My daily target potassium gonna be aprox 3.3 ppm

I will not gonna use KNO3 because I will get too much NO3. And I will partly get nitrogen from urea and ammonium
I'm not going to use K2SO4 because I will get S in the water and I don't know what this does in my tank
I'm not going to use KCl because I will get CL in the water and I don't know what it does in my tank
The advantage of K2CO3 is that it also increases my hardness slightly so I don't have to add KH additives, only GH supplements.

 

[Andy Pierce]

My understanding (which might be wrong) is that SO4 doesn't do anything in the tank, making XSO4 a generically good choice if you only want more X.

 

[_Maq_]

My daily target potassium gonna be aprox 3.3 ppm

It's extremely unlikely that your plants need that much. Impossible, I think. Excess potassium can easily lead to nutrient imbalances.

The advantage of K2CO3 is that it also increases my hardness slightly so I don't have to add KH additives, only GH supplements.

Yes, but what's the advantage of increasing alkalinity (KH)?

I'm not going to use K2SO4 because I will get S in the water and I don't know what this does in my tank

Nothing bad. Sulfates are a ubiquitous component of natural waters. Sulfur is an essential element for all life, incl. plants.

I'm not going to use KCl because I will get CL in the water and I don't know what it does in my tank

Nothing bad. Chlorides are a ubiquitous component of natural waters. Plants uptake chlorides readily to maintain equilibrium of internal fluids.

 

[hasan66]

Urea and NH4 components are not sufficient as a complete nitrogen source. It would be better if you use a NO3/NH4 combination because I used both of them together. Urea and NH4 cannot provide full performance.

 

[Zeus.]

Urea and NH4 components are not sufficient as a complete nitrogen source. It would be better if you use a NO3/NH4 combination because I used both of them together. Urea and NH4 cannot provide full performance.

Why not? Once Urea or NH4 land in the tank it's only a matter of time before its converted to NO3

 

[hasan66]

Why not? Once Urea or NH4 land in the tank it's only a matter of time before its converted to NO3

I couldn't get any performance in RO water, maybe it didn't have enough nickel to work with.

 

[John q]

I couldn't get any performance in RO water, maybe it didn't have enough nickel to work with.

And here lies the problem with playing whack a mole with ferts.
Assuming you add some salts, minerals to the water the likely hood is that you'll also be adding some amount of Ni into the mix, probably ppb, but that's enough, isn't it? If you're not sure add some nickel, but be careful of Ni toxicity 😀

 

[hasan66]

And here lies the problem with playing whack a mole with ferts.
Assuming you add some salts, minerals to the water the likely hood is that you'll also be adding some amount of Ni into the mix, probably ppb, but that's enough, isn't it? If you're not sure add some nickel, but be careful of Ni toxicity 😀

I will also say this: I will remove the resin filter from the RO filter. In this way, if I get 4-8 ppm instead of 0 ppm, maybe I will get some nickel.

 

[hasan66]

And here lies the problem with playing whack a mole with ferts.
Assuming you add some salts, minerals to the water the likely hood is that you'll also be adding some amount of Ni into the mix, probably ppb, but that's enough, isn't it? If you're not sure add some nickel, but be careful of Ni toxicity 😀

Or I will add about 1 liter of tap water.

 

[_Maq_]

I'm using solely RO+DI water (EC = 1 µS/cm) and mineralize it completely for years. I never dose any nickel and molybdenum. I don't feed any fish. In spite of that, I've never encountered deficiency of these two elements. Aside from mineral salts impurities, dust and pollen seem to be sufficient sources.

 

[Cor]

It's extremely unlikely that your plants need that much. Impossible, I think. Excess potassium can easily lead to nutrient imbalances.

If you find dosing daily 3.3ppm potassium extremely unlikely; what do you think is a good target of potassium for a high light tank?

 

[_Maq_]

what do you think is a good target of potassium for a high light tank?

10 mg/L NO3
1 mg/L PO4
2 mg/L K
6 mg/L Mg
20 mg/L Ca
Front loading, 50 % weekly WC.