How to Clear (and Prevent) Cloudy Swimming Pool Water

Cloudy Swimming Pool Water - The Common Causes

Number One Reason?  Lack of chlorine or SoftSwim "C" Clarifier.

You absolutely must maintain a chlorine or SoftSwim "C" level in your pool 100% of the time.

* If the pool goes without chlorine (or "C") for a 12 - 24 hours, your
pool water may experience SLIGHT cloudiness.

Usually a double shock treatment will be enough treatment to fix the problem and then leave enough residual chemical to protect the pool water from new threats.

* If the pool goes without chlorine /SoftSwim "C" for ALL of April and May with a winter cover still on the pool, you will experience ALL sorts of problems (and expense).

A double shock treatment will NOT be enough.



How Much Is Enough?

SoftSwim "C" Test Strips (square on the right)
The top strip has a great "C" level - dark purple.
The bottom strip has a zero "C" level - pink, no color change.

How then do you know if you have added the correct amount of sanitizing chemicals to kill the bacteria and algae in your pool water?

The only way to know is to test your pool water frequently!

Test daily early in the spring (or if you are new to pool ownership). Once you are confident you are maintaining a good chlorine / SoftSwim "C" level, then testing once a week should be sufficient.

Chorine Test Strips (square 2nd from the left)
Top strip, a great chlorine level of at least 5 ppm - dark purple.
Bottom strip, 0 chlorine level - yellow, no color change.

Testing after a heavy rain or heavy use (like a pool party) is also a good idea to detect a decline in sanitizing levels.

Test at home with test strips. "OTO" yellow drop kits are not preferred to test for free and available chlorine residuals. Bring a sample to PoolCo for complete testing at least 3 times a year: when you open the pool, after the 4th of July and before you winterize your pool.

Don't let chlorine or SoftSwim levels fall to low levels. 



"Tug of War"

Your pool is essentially in a "tug of war" of pool water vs. nature (algae/bacteria, etc.).  Pool chemical levels create a "barricade" to keep the "enemy" out.

Low levels are easily and quickly "knocked" down by bacteria and algae.

Your best defense against new invading algae and bacteria is to maintain chlorine and SoftSwim levels at the upper end of the safe and proper chemical ranges.


Why you should look at the pool every day.  

Does it look brilliant and sparkling? Or does it seem dull?

Why? Algae is either the beginning or
ending of a cloudy water problem.

Live algae is in the swimming pool pool starts as dull, hazy pool water. Because algae multiplies extremely rapidly, the pool will then go from cloudy to green ("mysteriously") overnight. If you are looking at the pool daily you can see this happening before is becomes a huge, expensive problem. Verify by testing the water and you will discover there is NO chlorine or SoftSwim "C". Immediately add a double dose of shock treatment and bring a sample PoolCo to have the water analyzed and receive further instruction.

Dead algae is still in the swimming pool pool. Okay, now you have a great chlorine or SoftSwim "C" residual on your test strip - but the pool is still really cloudy blue, gray or yellow. Dead algae are quite difficult to remove, especially with sand or cartridge filters. Special instructions are needed to quickly turn this situation around. Otherwise your pool water may remain cloudy all summer.


Other Causes - Some Common, Some Not So Common:

Rarely is cloudy water caused by just ONE issue. Normally it's a combination of things happening or not happening.

Filtration System:
Pool pump not running long enough. It must run a minimum of 10 - 12 hours a day.

Air leak from the suction side of your filtration system.

Low pool water level allowing pool skimmer to suck air.

Dirty Filtration System. Change sand yearly in non-chlorine (Softswim, Baquacil, etc) pools. Chemically clean every 4-6 weeks with StripKwik or Softswim Filter Cleaner.

Pool needs to be backwashed. However, backwash filter only when necessary (when pressure increases on pressure guage and circulation of the water has slowed).

Swimming pool pump strainer basket extremely full of bugs, leaves, pine needles, etc.

Pump impeller all stopped up with leaves, pine needles, etc.

Filter solidified with calcium or other minerals.

Cartridge swimming pool filter cartridge needs to be replaced. The filters lose their effectiveness each year. If the "pleats" have collapsed the filter is useless. If the filter has not regularly and consistently been chemically cleaned it will be clogged and is useless.

Multiport swimming pool valve gasket damaged.

Incorrect sand used instead of swimming pool filter sand.

Pool Chemicals:

High pH or Total Alkalinity.

Calcium hypochlorite pool shock or chlorinating powder used incorrectly. 

High calcium in swimming pool fill water.

Adding chlorine to a Baquacil or Softswim or other off brand of non-chlorine pool.

Adding copper algaecide to Baquacil or Soft Swim or other off brand of non-chlorine pool.

Overdose of swimming pool clarifier. (A little goes a long way.)

Overdose of stabilizer WAY too high ( > 200 ppm).

Use of copper ionizers or liquids, without sufficient shocking.

Repeated use of (cheap, gallon sized) "foamy algaecides" to "prevent" pool algae.

Other Factors:
"High Bather Load" - a lot of people in the pool and/or for a extend period of time. The smaller the pool the more likely cloudy water will happen 2 - 24 hours later.

Too much "Swimmer Waste" - too much sweat or (yuck) urine in the pool.

Excessive tree pollen in pool.

Dust blown into pool.

Pool vandalized with soap, detergent, motor oil, etc.

Large "Wedding Cake" style in-pool steps used in SoftSwim or Bacquacil pools.

Not brushing pool walls weekly to remove biofilm.

Want more?
Here's a link to THE best list of causes you'll find ANYWHERE on the internet:
Par Pools (BioGuard Dealer located in Connecticut) Cloudy Water List