If shock and the act of shocking the pool (primarily when to shock the pool) are the most confusing topic for pool owners, the relationship between Alkalinity and pH are almost equally confusing.
Water is balanced when the Alkalinity, pH, and Hardness levels are all within their ideal levels. Therefore, chemicals for adjusting the Alkalinity, pH, and Hardness levels are known as water balancers (also called water balancing chemicals).
The Alkalinity level of the pool water is closely related to the pH level. While pH measures how acidic or alkaline the pool water is at any given time, the Alkalinity – which can also be called the Total Alkalinity – measures the overall amount of alkaline material in that water. For a pool to be balanced, some alkaline material is desired in the water.
Any discussion about Alkalinity really will require mention of pH too.
You can read the Pool Manual for additional information about balancing pool water, Alkalinity, pH, and the relationship between the pH and Alkalinity levels for balancing pool water to help maintain optimal water chemistry.