Swimming Pool Blog

How to Clear Up Cloudy Pool Water

How to Clear Up Cloudy Pool Water
by Rob Cox
, August 9, 2019


Cloudy Pool Water

Cloudy pool water can be dangerous, In 2011, a young woman laid at the bottom of a swimming pool for two days, until some late night fence-jumping teenagers discovered her body in the pool.

Lifeguards had days earlier closed the deep-end of the pool for safety reasons just minutes after the drowning, unaware that the unsafe water condition had already claimed a life. story

Cloudy pool water can also present other unhealthy issues. Cloudy water is unsafe for diving because you can't see the bottom, unsafe for swimmers because lifeguards can't see the bottom, and the water is likely unsanitary, as well.

Cloudy pool water usually indicates insufficient filtering and/or insufficient sanitizer, or incorrect water balance. Swimming in cloudy water could mean an increased risk from waterborne pathogens such as E. coli and Pseudomonas, or the chlorine-resistant protozoan known as Cryptosporidium.

How to Prevent Cloudy Pool Water:

  1. Maintain proper water balance. Chlorine and pH levels should be maintained at 1.0-3.0 ppm and 7.4-7.8.
  2. Proper levels of calcium hardness and total alkalinity help to prevent solids from precipitating out of solution.
  3. Pool pumps should run long enough daily to filter all of the water at least once, twice during warmer months.
  4. Shower before swimming. Cosmetics, hair and skin lotions, deodorants, all contribute to cloudy pool water.
  5. Super-chlorinate the pool at the first sight of hazy water conditions, before it turns cloudy and then murky.
  6. Cyanuric Acid or stabilizer should be 30-50 ppm, to help reduce the summer sun's effect on chlorine levels.

How to Fix Cloudy Pool Water:

  1. Clean pool thoroughly to remove all organic debris.
  2. Balance the pool water. If your Test Kit is old or untrustworthy, take a sample to a local pool store for testing.
  3. Run the filter 24/7 until clear. Wait to backwash or clean filters until the pressure gauge is 7-9 PSI higher.
  4. Shock the pool with 2 pounds of Granular Chlorine or Non-Chlorine Shock per 10,000 gallons of water.
  5. Use a Pool Clarifier, which acts as a coagulant for very small particles. Don't overdose, follow label dosage.
  6. Make sure that your pump is operating at peak power by cleaning pump baskets and skimmer baskets.
  7. If small particles are passing through your filter while vacuuming, fill the pool, then vacuum to waste.

When Cloudy Pool Water Won't Clear Up:

  1. Consider that your pool filter is undersized or that new filter media (sand, cartridge, grids) may be needed. 
  2. If you have a DE pool filter, disassemble and clean thoroughly, and inspect the grids for damage.
  3. Is the filter pressure normal? If the PSI is lower than normal, the impeller, basket or pipes may be clogged.
  4. Water can bypass the filter from a faulty backwash valve. Again, look for lower than normal filter pressure.
  5. Is your pump operating correctly? Make sure the motor is not overheating and cycling on and off.
  6. Is air entering the filter? Air leaks before the impeller, or from low water level, or stuck skimmer weirs.
  7. Are there external sources of heavy dust, pollen or mudslides entering the pool when you're not looking?


Cloudy pool water is rarely caused by a single problem, but a combination of issues in 3 areas - Filtration, Circulation and Sanitation. Optimize all three areas and you will be in good shape soon.

And remember that cloudy pool water has proven itself to be dangerous to swimmers and divers. If you cannot see the bottom of the pool, close the pool immediately, and do not allow pool use until you can see the bottom of the pool.



 - Rob