ADA Aquasoil, Does it "soften" water?

[KrishP]

Hi Everyone,

I while back, I read on the internet that aquasoil reduces the GH, KH and pH of the water and this was why shrimp keepers used it for CRS. Has this been true for anyone?

 

[BigTom]

I don't test GH or KH but have fairly soft water and found that Aquasoil significantly reduced the pH in my nano tanks compared to an inert substrate. However, after a period of time (6 months or so, I can't remember exactly) the effect wore off and now it has relatively little effect.

 

[parotet]

I doubt it can 'soften' the water, as hardness will depend mostly on the water you use in the tank. What I have noticed in a new setup is that at the beginning aquasoil will leach several substances, such as humic acids (probably something more I don't know) that will give you lower pH readings compared with the water used to fill the tank...

 

[Alastair]

If your using ro water anyway in a tank with specialist soils that will increase its life span as its not having to work as hard to reduce ph gh etc

 

[Mats A]

My GH and KH are basically the same with ADA Aquasoil as with any other substrate. But as BigTom say it reduces PH a bit

 

[dw1305]

Hi all,

I doubt it can 'soften' the water, as hardness will depend mostly on the water you use in the tank.

These active substrates can actually soften the water, the reason is that the substrate has CEC (cation exchange capacity), and probably a low "base percent saturation". This means that it will extract Ca++ ions etc from the water column and exchange them for H+ ions.

The extent of ion exchange is dependent upon both the lyotropic series and the concentration of ions in solution. Monovalent ions like Na+, K+, NH4+ and H+ will all preferentially be swapped for divalent cations Ca++, Mg++ etc., but the reduction in pH would strongly suggest that H+ ions are being exchanged, as the other monovalent ions are bases and would raise pH.

However, after a period of time (6 months or so, I can't remember exactly) the effect wore off and now it has relatively little effect.

This is because this is "cation exchange", meaning that eventually a stable situation will result. In the stable state if we added very pure or slightly acidic water pH would rise as the increased conc. of H+ ions in the new water will lead to them being exchanged for Ca++ ions in the substrate.

cheers Darrel

 

[KrishP]

Hi Darrel,
Thanks for the response, I find learning about pH interesting as I am learning about it in A-Level chemistry! So from that I am guessing aquasoil will lower the pH and GH, but leave the KH same. With the effect lasting 6 months it can not be a long term way of lowering the pH,GH and KH

 

[dw1305]

Hi all,

So from that I am guessing aquasoil will lower the pH and GH, but leave the KH same.

I'm not sure, it would depend upon the lyotropic series for anions, and the anion exchange capacity of the substrate. Looking at this link <NC State Soil Science> it looks like HCO3- is the most strongly bound anion, so potentially it may be swapped for Cl- ions etc, lowering the dKH as well.

With the effect lasting 6 months it can not be a long term way of lowering the pH,GH and KH.

Yes it is going to be like any ion exchange resin etc, how long it remains active for is going to depend upon the salts concentration in the water. If you have high conductivity, alkaline water it softening effects are going to be fairly short-lived.

cheers Darrel

 

[KrishP]

I measured my GH which was 6 and my KH was 3. The pH was 7 that was measured straight from the tap