ADA Amazonia too acidic?

[Zebra]

Haha sorry a bit random,

just these really cool shiny coloured sealable bags @newbreed aquatics sell their food in. ? I've been trying to find out where to order them to use for packaging my own fertilisers.

I think they are aluminium/Mylar? 

Edited December 31, 2016 by Zebra

[viridisornatus]

Lol no worries :)

 

So an update: About 1 month old soil now, after a few more total WC, the water is about pH 5.2 according to 2 calibrated pH pens. This is really surprising and frustrating lol.

[newbreed]

On 28 December 2016 at 10:53 PM, Zebra said:

Always good to pay it forward when I get lucky
Can you please send me some info on the food bags you use Jamie  @newbreed They are very nice and I wanted to order some to package dry ferts. Much appreciated mate.
Cheers.

Sorry for delay. Message just sent. 

[Zebra]

thanks heaps :) I ordered some today cost about 25c each.

cheers

[viridisornatus]

Update: Several total water changes later, pH is around 4.8-5.0. It seems to take longer to get that low but still gets there. What prevents the soil from continuously leaching acid instead of buffering to a certain pH?

On the plus side, the filter is cycled and processing a couple PPM ammonia in 24 hrs at this point, growing slowly.

 

[jayc]

31 minutes ago, viridisornatus said:

What prevents the soil from continuously leaching acid instead of buffering to a certain pH?

The amount of soil you use. Use too much and it buffers the pH very low until it reaches equilibrium.

[viridisornatus]

Thanks Jayc :) So with a small/normal amount of soil, the acidification is supposed to be slow enough that it is counteracted by something?  In the absence of carbonates or water changes, why wouldn't the acids eventually reach the solubility limit? Biodegradation?

[jayc]

19 hours ago, viridisornatus said:

So with a small/normal amount of soil, the acidification is supposed to be slow enough that it is counteracted by something?

yes, i believe so. 

 

19 hours ago, viridisornatus said:

In the absence of carbonates or water changes, why wouldn't the acids eventually reach the solubility limit? Biodegradation?

I don't know if biodegradation is the right term for it, even if I have no better terminology to replace that term. The best I could think of is ... 'nature'. Your soil isn't the only thing in the tank that is reducing pH. The bacteria is producing more hydrogens during the nitrogenous cycle of ammonia to nitrates and thus also decreasing pH. The water surface and air is exchanging O2 and CO2, and also alter pH. If you add CO2 into the tank, that will reduce pH as well, as we all know. As you can see there are many factors involved, and it's difficult to isolate one as the many cause. But, reducing amount of soil can help. 

New soils will produce a greater pH altering affect, but will eventually subside to produce more stable readings. So if you have new soil, keep up with your water changes. Or you can reduce the amount of soil used at the start. Or even introduce some carbonates in the form of shell grit or egg shells, or coral skeletons.

 

Your soil might be reaching it's solubility limit as it is now. pH4.8 should be about it's limit. 

If you did nothing else, that should be as low as it gets. 

What soil are you using BTW? ADA Amazonia?

<edit> - just read the first post. Amazonia has been know to drop pH into the 4's when new. It's common, when you use a generous amount. It will slow down when it matures, but you can help it along with some carbonate input as suggested above.

Edited January 31, 2017 by jayc

[viridisornatus]

Thanks Jayc. That's very interesting because it implies that if one stopped doing WC, the soil would still exhaust, albeit much much slower. Are 10% weekly WC in an established tank enough to prevent the soil acids from ever reaching saturation?

[viridisornatus]

Update: 3 months later, after multiple WC, weeks of lots of calcium carbonate added to buffer above pH 6.5, the soil still buffers below pH 6 on its own within days of a total WC.

I am wondering if it's time to give up on this soil? Scoop most of it out, keep the rooting plants in "pots" and go with a fine sprinkling of soil everywhere else?