Cloudy with a Chance of Complaints

10 common causes of hazy spa water and how to address them

ByTim Rodger

Some of the most common client complaints our industry hears are about cloudy spa water. It’s a frequent issue — and one with many causes and cures. I’ve compiled a list of the most likely culprits behind cloudy hot tub water, along with remedies you can share with customers when they ask for help. 

1. Dirty filters

Filters can only hold so much, and when they are full, debris in the water cannot be removed, staying suspended in the spa water and making it cloudy. Proper and timely filter cleaning practices, including the use of cleaning agents, are essential to maintaining clear water. Installing a new or properly cleaned filter will also clear water.

2. Bather overload

Four people in a hot tub is the equivalent of 200 people in a swimming pool. If bathers don’t shower before using the spa, they are using it as a bathtub and introducing contaminants, which can easily overwhelm the spa and cause cloudy water. To minimize this, ask that bathers shower thoroughly before using your spa. 

Changing the water is usually the fastest, least expensive way to remedy cloudy water caused by bather overload. If that’s not possible, increase filtration times, install clean filters, shock the water, use a water clarifier and continue this regimen until the water clears. As the water becomes clearer, the filter will get soiled and may require additional cleaning or replacement. 

3. High pH

Water that has high pH can quickly become cloudy or may even come out of the tap looking hazy. Balancing the pH to proper ranges will clear the water.

4. Metals in the water

When copper and iron oxidize, the result is discolored, cloudy water that often appears green, yellow or hazy. To clear it, shock the water, wait at least 24 hours and if the color persists, shock the water again and wait another 24 hours. Repeat as necessary — multiple applications may be required.  

5. Old filters

As filters age, the 20-micron holes in the fabric get worn out and become larger. While it may look good to the naked eye, an aged filter can be worn to the point where it will allow twice as much debris or more to pass through it as it did when it was new. A filter should be replaced after at most a year of use, or a dozen cleanings, whichever comes first.

6. Insufficient sanitizer

When sanitizer levels are low, impurities introduced to the water from bathers or other sources can overwhelm the sanitizer, resulting in cloudy and potentially microbiologically unsafe water. Maintaining sanitizer levels as per regulatory agency guidelines will prevent and correct cloudy water.

7. Insufficient filtration times

It takes time to filter debris from hot tub water. Make sure the spa is scheduled to filter for at least six hours per day, or if it uses a low-volume hush pump, it should be programmed for the longest duration, preferably 24 hours per day if possible. Proper filtration times will improve clarity and decrease the amount of spa water treatment product used to maintain water.

8. Debris in the water

Contaminants introduced from creams, deodorant and other body-care products can be so small that they pass through the filter, causing cloudy water. This can be corrected by using a water clarifier that will collect the debris into a larger mass that can be trapped by the filter, allowing the water to clear.   

9. Hot tub contamination

Mold, algae, fungus, biofilm and bacteria can cause cloudy water and will require you to decontaminate the spa. My article on white mold in the April 2024 issue of SpaRetailer includes directions on how to do so.

10. Filling with turbid water 

This happens most often when using water from a lake or a well. The water can contain tannins or oxidized metals such as iron oxide that can make the water cloudy. Shocking the water with chlorine will clear it, but multiple applications may be required.

While the above causes and cures can be used to help your client resolve their struggles, using them to educate your client beforehand can prevent many instances of cloudy water from occurring in the first place.

Tim Rodger is with the water care department of The Spa Marvel Company and is available to help you and your clients with water care questions seven days a week (but not 24 hours a day).

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