The quick answer
Cloudy water usually comes from ineffective sanitation, suspended debris, filtration trouble, poor circulation or scale-producing imbalance.
Do not swim without visibility
If the deepest area or main drain cannot be seen clearly, keep swimmers out. Visibility is a safety requirement, not merely cosmetic.
Check sanitizer and pH
Low effective sanitizer can allow growth, while high pH reduces chlorine effectiveness. Stabilizer changes how the chlorine reading should be interpreted.
Look at filter and flow
Full baskets, low water, a dirty filter or pump trouble reduce turnover. Compare pressure to the system’s clean baseline.
Consider recent events
A storm, heavy swimming, landscaping debris or a large addition may explain the timing. The cause determines the solution.
When to call for help
Persistent cloudiness, rising pressure, weak returns or repeated sanitizer loss should be evaluated. Avoid combining random products.