The state or level of Alkalinity acts as a buffer (resists change) for pH. Buffers are important because having the right amount and type of buffers keeps the pH from changing. If the alkalinity is too high it will raise pH. If there is low buffering (low alkalinity), it will lower the pH. Alkalinity and pH are related. Changing one will change the other.
|Chemical additive or action||pH||TA|
|Acid||Goes down||Goes Down|
|Soda ash||Goes up||Goes Up|
|Bicarbonate of soda||No change||Goes Up|
|Aeration and bubbling*||Goes up||No change|
*The pH of water can be raised without raising alkalinity by aeration or turbulence. Knowing how to do this will allow you to balance the water perfectly to pH 7.5 and alkalinity of 90 ppm in a matter of hours or maybe a day.