Buffering capacity and pH

Buffering capacity and pH

If your freshwater tank has a low KH, you can use baking soda (sodium bicarbonate NaHCO3) to increase the carbonate hardness (KH) of your water. This is also called buffering capacity or alkalinity. Adding baking soda will not increase your general hardness (GH). KH should be at or above 4.5 DH / 80ppm to keep pH from becoming acidic. I buffer my tanks up to 7dh to keep KH above 4dh by the next weekly partial water change.

When you dose the tank, dissolve the baking soda in water you've removed from the tank; then add the mixture slowly to the tank stirring to disperse. Shoot for raising pH by no more than .4 per day.

Calculate baking soda needed to raise KH by a specified amount.
Specify tank size and the KH increase you want to cause:
Gallons:
Desired KH change:
Which measure of KH? dh ppm
Teaspoons of Baking soda needed:

based on adding 1 t baking soda in 50 liters of water to raise KH by 4 dh.

Calculate resulting pH change
Specify starting and ending KH:
Starting KH:
Ending KH:
pH Change:

How much the change in KH will raise pH is calculated by taking the log of the expected change in KH log(ending KH/starting KH). e.g. if your starting KH is 40 and you take it up to 80 you should see log(80/40) = .3 increase in pH.

Google search: KH pH and "baking soda"

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