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Guides / Cloudy Water

Troubleshooting Cloudy Pool Water

Cloudy water is a symptom, not a diagnosis. Work through these causes in order — most cases are solved by step 2.

Step 1: Check filtration (the #1 cause)

  • Is the pump running 8–12 hours a day? Bump it to 24 hours until the water clears.
  • Check pressure: backwash sand/DE filters or rinse cartridges when pressure is 8–10 psi above clean.
  • Empty skimmer and pump baskets — restricted flow means unfiltered water.
  • Cloudy right after backwashing? Run the filter on rinse for 30 seconds first.

Step 2: Test and fix sanitizer + pH

  • Test free chlorine and pH first. Low chlorine with warm water is the classic cloudy-water combo.
  • Bring pH to 7.2–7.6, then shock in the evening per our Chlorine Calculator.
  • Keep the pump running and don't swim until free chlorine is back under 4 ppm.
  • If combined chlorine is above 0.5 ppm, the pool needs shocking regardless of how the water looks.

Step 3: Handle fine particles

  • If chemistry is balanced but haze remains, it is usually particles too fine for the filter.
  • Use a clarifier (binds particles so the filter catches them) for mild haze.
  • Use flocculant only for severe cases — it drops debris to the floor and you must vacuum to waste.
  • Brush walls and vacuum slowly so you don't re-stir settled debris.

When it's something else

  • After rain: Rain dilutes chemicals and washes in debris. Test, rebalance, and shock. See our Chemical Calculator.
  • High calcium + high pH: White, milky cloudiness can be calcium scale forming. Lower pH carefully and retest.
  • Green tint: That is early algae, not just cloudiness — see Algae Treatment.
  • Still cloudy after 3–4 days of correct chemistry and filtration? Check for channeling in sand filters, torn cartridges, or get a professional water test.