How to Clear Cloudy Pool Water: Complete Step-by-Step Guide

Tools & Supplies Needed

Find on Amazon: Taylor K-2006 Test Kit , Liquid Chlorine , Muriatic Acid

Quick Answer

Cloudy pool water is cleared by testing your water chemistry, balancing pH and alkalinity, shocking to the appropriate level based on your CYA (stabilizer) level, and running your filter continuously until the water clears. The key is maintaining shock level chlorine until all cloudiness disappears.

Step-by-Step Guide to Clear Cloudy Water

1. Test Your Water Chemistry
   Use a reliable test kit like the Taylor K-2006 to test FC (free chlorine), pH, TA (total alkalinity), CYA (cyanuric acid/stabilizer), and CH (calcium hardness). Record all readings as they'll guide your treatment plan.
2. Balance pH First
   If pH is above 7.6, add muriatic acid to bring it down to 7.4-7.6 range. High pH prevents chlorine from working effectively. Add 1 quart of muriatic acid per 10,000 gallons to lower pH by 0.2 points. Wait 2 hours and retest.
3. Adjust Total Alkalinity if Needed
   If TA is outside 80-120 range (60-80 for salt water pools), adjust using muriatic acid to lower or sodium bicarbonate to raise. Target 100 ppm for most pools.
4. Determine Your Shock Level
   Based on your CYA level, determine the required shock level FC:
   • CYA 30: Shock level 12 ppm FC
   • CYA 40: Shock level 16 ppm FC
   • CYA 50: Shock level 20 ppm FC
   • CYA 60: Shock level 24 ppm FC
5. Calculate Chlorine Needed
   Use liquid chlorine (sodium hypochlorite) - typically 1 gallon raises FC by 10 ppm in 10,000 gallons. Calculate how much you need to reach shock level and add it all at once, preferably in the evening.
6. Start Continuous Filtration
   Run your pool pump and filter 24/7 until water clears. Clean or backwash your filter before starting. If you have a cartridge filter, have spare cartridges ready as they'll need frequent cleaning.
7. Brush Pool Surfaces
   Brush walls, steps, and floor thoroughly to dislodge any particles or biofilm that may be contributing to cloudiness. Pay special attention to areas with poor circulation.
8. Test FC Every 8-12 Hours
   Test your FC level twice daily. If it drops below shock level, add more liquid chlorine to bring it back up. The FC will drop quickly initially as it kills contaminants.
9. Maintain Shock Level Until Clear
   Continue adding chlorine to maintain shock level until:
   • Water is crystal clear
   • FC level holds steady for 24 hours without significant drop
   • CC (combined chlorine) is 0.5 ppm or less
10. Clean Filter Regularly
    Clean cartridge filters daily or backwash sand/DE filters when pressure rises 8-10 psi above clean pressure. Dirty filters cannot clear cloudy water effectively.
11. Consider Clarifier if Needed
    If cloudiness persists after 48 hours of proper shocking and filtration, add a clarifier like Natural Chemistry Pool Perfect or BioGuard Polysheen Blue. Follow label directions carefully.
12. Return to Normal Operation
    Once water is clear and FC holds steady, reduce chlorine to normal operating level (typically 2-4 ppm based on CYA level) and resume normal filtration schedule.

Common Causes of Cloudiness

Understanding why your pool became cloudy helps prevent future issues:

• Poor filtration - Dirty filter, insufficient run time, or undersized equipment
• Chemical imbalance - Low chlorine, high pH, or improper alkalinity
• Environmental factors - Heavy rain, wind-blown debris, or algae spores
• Bather load - Too many swimmers without adequate sanitation
• Equipment problems - Malfunctioning pump, clogged skimmers, or circulation issues

Important Safety Notes

Warning: Never swim in cloudy water as visibility is compromised and you cannot see someone in distress. Always add chemicals with pump running for proper circulation, and never mix different chemicals together.

Expected Timeline

Most cloudy water clears within 24-48 hours when properly treated. Severely cloudy or green water may take 3-7 days. The key is patience and maintaining proper chemical levels throughout the process.