Does the pH/KH/CO2 relationship still hold for Singapore ta

[PeterGwee]

Just wondering after helpful feedbacks from likes of Vinz and Bclee...but cannot really find the conclusion whether the relationship still hold for Singapore tap water or not. Anybody have any answer []

[PeterGwee]

Just wondering after helpful feedbacks from likes of Vinz and Bclee...but cannot really find the conclusion whether the relationship still hold for Singapore tap water or not. Anybody have any answer []

[PeterGwee]

Just wondering after helpful feedbacks from likes of Vinz and Bclee...but cannot really find the conclusion whether the relationship still hold for Singapore tap water or not. Anybody have any answer []

[PeterGwee]

Just wondering after helpful feedbacks from likes of Vinz and Bclee...but cannot really find the conclusion whether the relationship still hold for Singapore tap water or not. Anybody have any answer []

[vinz]

Peter, was re-reading Chuck Gadd's article again... read something interesting in the first myth "Myth: A Low KH results in a larger pH swing when adding CO2".

[PeterGwee]

Ermmm..vinz..yes..Singapore water when injected with CO2 without addition of baking soda or KH up powder tend to sky dive after short period. Does that mean the relationship still stands like Bclee said?

[vinz]

Hmmm... actually, I was focusing more on the fact that we don't have to maintain 4 to 6 KH as recommended by many sites. We can stick to say 2 KH, so the start and end values of pH are lower.

[bclee]

With same bubbling rate, CO2 somewhat dissolved faster/more in water with 0°KH compared with one with 1~2°KH.

Just a simple equilibrium.
CO2(aq) + H2O <---> H+ + HCO3-

When KH is zero, there is no HCO3- present in the water. Therefore, the reaction will swing to the right. More H+ will be produce and the pH drop.

When KH is high, HCO3- concentration is high. You have to add much more CO2 to "push" the reaction to the right (producing more H+ to lower the pH).

I hope you can understand the relationship. For you guys who knows, the simplified equation for the above reaction is something like this. (if my brain is still working correctly despite of the recent cases of bad sectors[])

K = conc(CO2)/{conc(H+)*conc(HCO3-)}

K = equilibrium constant which is constant at fix temperature.

conc(CO2) = concentration of dissolved CO2
(maybe = bubbling rate)

conc(H+) = concentration of H+
(conc. H+ increases, pH reduces.)

conc(HCO3-) equivalent to KH.

You can try to work out mathematically the relationship of changing concentration of each component.

BC