Problem with carbonate stones - ruined aquasoil for good

[Pique]

Is it possible that carbonate stones can totally ruin aquasoil and similar material? 

Had wio artist terra soil and without the stones I tested the ph about 5,5, thought that a bit low so I dumped few carbonate stones in to the test bucket and see how it worked.... the ph sky rocketed to 8. 

Pulled the stones out and changed the water to see if the ph would go down again... but nothing happens! the ph stays high! Has the carbonate stones like ruined the soil for good and kind of nullified the soil´s all good properties for good? Is there anything to be done? Has the soil "sucked" in all the carbonate stones hardening minerals and it´s useless now?

Luckily I didn´t do this in my aquariums, but in a separate test bucket...

Has anyone experienced similar?

I´d be thankful for any help in this :)

[Guppysnail]

Maybe @Sarina would know.  Sounds like a materials question 

[Sarina]

On 9/23/2024 at 1:57 AM, Pique said:

Is there anything to be done? Has the soil "sucked" in all the carbonate stones hardening minerals and it´s useless now?

Technically this is a chemistry question, but essentially you have altered the buffering capacity of the aquasoil, yes. 

Carbonate ions are positively charged, and like to stick to negatively charged ions to form stable bonds, and by adding a lot of carbonate ions to a substrate that naturally bonds to positively charged ions via high cation exchange capacity (CEC), your soil is now pretty much inert, as the cation exchange capacity has been depleted. Carbonate isn’t really used by plants like other nutrients, so carbonate ions take up space where other nutrient ions would normally be held and passed between the soil and plant roots. 

Here’s an illustration of what happens with high CEC soil:

 

You can still use the soil, however it won’t buffer the water anymore, and it will no longer be a high nutrient density substrate.
 

I hope that makes sense, let me know if I have missed anything or if anything is incorrect because I’m writing this at 6am 😅

[Rube_Goldfish]

On 9/27/2024 at 7:09 AM, Sarina said:

Technically this is a chemistry question, but essentially you have altered the buffering capacity of the aquasoil, yes. 

Carbonate ions are positively charged, and like to stick to negatively charged ions to form stable bonds, and by adding a lot of carbonate ions to a substrate that naturally bonds to positively charged ions via high cation exchange capacity (CEC), your soil is now pretty much inert, as the cation exchange capacity has been depleted. Carbonate isn’t really used by plants like other nutrients, so carbonate ions take up space where other nutrient ions would normally be held and passed between the soil and plant roots. 

Here’s an illustration of what happens with high CEC soil:

 

You can still use the soil, however it won’t buffer the water anymore, and it will no longer be a high nutrient density substrate.
 

I hope that makes sense, let me know if I have missed anything or if anything is incorrect because I’m writing this at 6am 😅

Is there any way to reverse or undo the depletion? To strip the carbonate back out from the soil?

[Sarina]

On 9/28/2024 at 10:40 AM, Rube_Goldfish said:

Is there any way to reverse or undo the depletion?

Over time if the substrate is repeatedly exposed to very acidic conditions, the carbonate ions may instead bond to hydrogen ions instead of the substrate, but this would take a very long time and is probably not worth it. 

[Pique]

Hi!

Thanks for all the responses, truly appreciate☺️ But what bummer that the soil's good buffering qualities and nutrients are lost😕 Really the good thing is that I did not buy tons of the soil to my bigger tanks and loose fish lives because the huge change in ph and money😅 

 

[Pique]

Began to wonder if the process would still go on if more substrate would be added on top the already nutrient depleted substrate🤔 Would the new substrate also become inert and poor of nutrients? Dare not to try, but all this scientific aprroach made me curious.