# Issue with Kh/K



## Flosam (19 Apr 2021)

Hi there! This is my 49ltrs tankconfiguration:
49ltrs (35x35x40cm)
Filter: JBL E402 with JBL original configuration of mechanic and biologic media.
Manado dark 
Lightning: Chihiros A351, 21watts, 3450lumen, 8000k with 7 power levels: 100% - 90% - 80% - 70% - 60% - 50% - 30% (it is actually set to 30%)
light period 8 hrs
Living stock: : 2 neritina natalensis, 2 Red cherries and 6 Amano Shrimp (caridina multidentata)
feeding: died leaves, and temporary algae. 
Water parameters: Kh10, Gh12, ph6.5 , NPK: 0, 0, 10 
Heater Eheim Jagger 75w 
Inflow glass pipe with skimmer, outflow glass pipe, CO2 drop checker, 26ºC, 2 redmoore roots, and Ryouh stones
Plants : Sagittaria subulata, anubias bonsai, ammania senegalensis (i was told it was going to grow to 15-20 cm but it actually is 35cms tall), nomaphila stricta.
Fert dossing: Seachem nitrogen, phosphorus, potassium and trace, dossing according to *this calculator*. I also add 2drops of Iron chelate EDDHA 0,06% (actually, no ferts are being dossed because of an issue relates with K, and Kh)
CO2: enough amount to keep the drop checker green, introduces with a Neo difusser
Started on 20/01/2021

This is my tank, and I’m having issues on K assimilation, I have been told  it is due to the high kh hardness, can you help me to solve this issue??? Does anybody know about it??

My saggittaria is not carpeting, and the stem plants are no fine... the one is doing wis anubia bonsai.

I’m doing weekly water change of 15ltrs with mineral water (kh1, gh1, ph5.3, tds16ppm) because my tap water is too hard (Gh+18, kh17, ph7.5 tds365ppm).

The issue I told before about Kh and K is that I have been told that my plants are not doing well because the carbonates that raise the Kh are blocking the plants assimilation of K. That’s why I do weekly WC with mineral water instead tap water.

Thanks in advance for your help!!


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## Flosam (19 Apr 2021)

I forgot that I have also been told that Manado is going to “eat” almost all I add to water (chemistry) and returns cations untill it saturates, then it won’t “eat” anything else.


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## dw1305 (20 Apr 2021)

Hi all, 
Welcome @Flosam,  we've have/had a number of <"Spanish members">. 

Can we have a picture of the tank? It will give us a bit more chance of assessing plant health,  


Flosam said:


> Fert dossing: Seachem nitrogen, phosphorus, potassium and trace, dossing according to *this calculator*. I also add 2drops of Iron chelate EDDHA 0,06% (actually, no ferts are being dossed because of an issue relates with K, and Kh)


You probably need to dose some nutrients. 


Flosam said:


> This is my tank, and I’m having issues on K assimilation, I have been told it is due to the high kh hardness, can you help me to solve this issue??? Does anybody know about it??


Don't listen to whoever told you that.  Potassium compounds <"are all soluble">, so potassium (K+) ions will remain in solution and plant available. If you have a lot of Ca++ ions they can interfere with the uptake of other cations, but for the vast majority of plants this isn't ever an issue. 


Flosam said:


> forgot that I have also been told that Manado is going to “eat” almost all I add to water (chemistry) and returns cations untill it saturates, then it won’t “eat” anything else.


If it is an active substrate it will exchange ions. Cation Exchange <"isn't  entirely straight forward">.  

cheers Darrel


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## Flosam (20 Apr 2021)

Thanks Darrel!!!, so according to my tank water parameters and to my tap water parameters, if I gradually change the tank water to tap water (declorinated of course) what should I have to expect once all the tank is finally full with tap water?? Will manado still exchanging ions and changing my tank water parameters??


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## ceg4048 (21 Apr 2021)

Flosam said:


> The issue I told before about Kh and K is that I have been told that my plants are not doing well because the carbonates that raise the Kh are blocking the plants assimilation of K. That’s why I do weekly WC with mineral water instead tap water.


This is false. Hard water has nothing to do with blockage of K+ assimilation.
I advise to stop worrying about K or KH and concentrate more on keeping your tank clean with regular water changes, dosing your nutrients regularly and to pay close attention to your CO2. Your plants really do not care about your water parameters and neither do they care about what your Manado is doing to the water. The more you worry about water parameters the more troubles you will have.

Cheers,


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## Flosam (26 Apr 2021)

Thanks a lot Ceg for your answer, it helps me a lot!!


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