It's a way to measure the acidity or alkalinity of water. This is the most important part of chemical balance because it protects the equipment, allows the sanitizer to do its best job and increases swimmer enjoyment.
Your best course of action is to take a sample of water to The Pool & Spa House and have a member of the friendly retail staff test the balance of your pool water for personalized instruction on the best corrective measures.
Some suggestions may be:
Adjust the pH. High pH can cause cloudy water
Clean the filter with Strip Kwik for better filtration