Copyright by KD Nishikigoi 2010. All rights reserved.
Carbonates Support pH But Can Be Exhausted
Carbonate balance is a long subject but I intend to keep it brief. I will over
simplify for greater understanding. As we mentioned before, pH is a
measurement of Hydrogen ions in the system. Hydrogen ions can come from
the reduction of Ammonia and several other biological processes. We
mentioned that in the absence of carbonate molecules, these Hydrogen ions
would drive down the pH.
Carbonate molecules come from several places. Sometimes, they occur
naturally as a result of the dissolution of rocks like Limestone and Dolomite.
These rocks are made of Calcium and Magnesium carbonate. When these
rocks dissolve they release those minerals, plus Carbonates.
Unnaturally, the carbonates may be supplied directly in the form of Sodium
bicarbonate. Indeed this is nothing more than Baking Soda.
The carbonate molecule exists in a balance with the environment. When
Hydrogen ions become abundant, the carbonate molecules pick up the
extras, which prevents the pH from falling. When hydrogen ions become
scarce, as in a high pH [to assign a number; 8.3] the carbonate molecules
will liberate some Hydrogen ions.
The net effect of the carbonate molecules on the water is to hold the pH at
some, constant level. This is why there is a benefit in knowing the “number”
[quantitative] measurement of carbonate activity.
When you’re measuring the carbonate levels in a system, it’s known as a test
of the “Total Alkalinity” of the system. There are affordable Total Alkalinity test
strips at most major garden centers and pet shops. Pools supply stores also
provide very reliable strips that measure TA.
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