[ampalsson]

Here in Iceland where I live is quite hard to get access to powders for fertiliser making
What I have managed to source is Potassium Nitrate (strangely, that was the easy part), Magnesium Sulphate and I have some CSM+B on order via Amazon
I have been complately unable to find any Potassium Sulphate but I have been able to find Potassium Carbonate (not Bicarbonate)
The water where I live is quite soft. KH is around 3dKH
My question is - given the soft water, can I use the Potassium Carbonate as a replacement for Potassium Sulphate as long as I keep an eye on the Alkalinity?
Any advice would be greatly appreciated

 

[diverjoe]

Would actually be better


Sent from my iPhone using Tapatalk Pro

 

[BOTIA]

You can buy high quality , dry premixed for relatively cheaply from. https://www.facebook.com/VI.NutraQuatics/
I use it is just as good as thrive or tropica ferts. At less than half the price. Just add 500ml distilled water per pouch and shake and Voila.

 

[ampalsson]

You can buy high quality , dry premixed for relatively cheaply from. https://www.facebook.com/VI.NutraQuatics/
I use it is just as good as thrive or tropica ferts. At less than half the price. Just add 500ml distilled water per pouch and shake and Voila.

Thank you for the recommendation. The problem is Iceland Customs. Trying to import any chemicals, even relatively innocent salts like Potassium Sulphate will get them all defensive and really isn´t worth the fight.
I have found a source for Magnesium Sulphate (in 5kg bags) and have already bought mail-order some Potassium Nitrate. In the same order, I got Potassium Carbonate. I can see where I can make up my own NPK brew and even if I have to dose Iron and Traces with Seachem stuff, I don´t think I´m in such a bad spot

 

[Edward]

Hi
The choice of K compound depends on your fish load and water changes. If you have high fish load than you need to dose more K than NO3 but if you have low fish load than vice versa. Similarly, if you are doing larger water changes than you can get away with dosed abnormalities but with smaller water changes the dosing must be more precise. For example:

14 ppm K, K2SO4
14 ppm K, 1 dKH, K2CO3
14 ppm K, 22 ppm NO3, KNO3
14 ppm K, 5 ppm Cl, KCl

K2SO4
Ideal source of K.

K2CO3
Can live with 1 additional dKH when adding 14 ppm K but you need to add it only to new replaced water to keep KH consistent.

KNO3
Can use with very low fish load and strong light, high CO2, fully planted and water changes.

KCl
Can use as a source of K but need to do water changes before adding more.

Also, having no source of PO4 can work only under low light and high fish load. Anything else will need PO4 addition to keep plants alive. You need to find KH2PO4. And I would recommend any TDS tester and finding local tap water report regarding Ca and Mg concentrations.

 

[ampalsson]

I have been toying with making PMDD lookalike using the K2CO3
Everything looks good except the mixture is milk-white
I am assuming this is because of solubility issues with the K2CO3????
After the solution sits for an hour or two, the white deposits sink to the bottom and I have a crystal clear liquid at the top.
What would be the deposits falling out?
Is there any reason not to use the clear portion of the liquid?

 

[kozlany]

Have you tried a hydrophonics supply place? Seems to me there would be a lot of greenhouses in Iceland.

I have very soft water where I am, like mostly snow melt. I use GH booster from NilocG and potassium nitrate, and potassium phosphate. Hasn't been the need to add more K. I sometimes even worry I might have too much.
https://www.nilocg.com/shop/nilocg-gh-booster-aquarium-planted-tank/

For carbonate hardness I use the very unscientific handful of chicken grit, which is just crushed limestone and oyster shell. Works for me and it's easy to find.

KCL they sell in grocery stores as salt substitute.

 

[ampalsson]

Thanks for the reply.
Unfortunately, I haven´t been able to find any hydroponics suppliers. Yesterday, I spoke with the other of a large greenhouse complex where they grow all kinds of flowers and fruit in greenhouses and he is helping me locate some. He told me Potassium Sulphate is not much used here.
Anyhow, the question really was about the solubility of K2CO3

Kind regards