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How To Clear A Cloudy Hot Tub | Canada Hot Tub Parts®

Posted by Canada Hot Tub Parts® on Oct 18, 2019

How To Clear A Cloudy Hot Tub | Canada Hot Tub Parts®

So you’re about to jump into your hot tub when you notice that the water is looking hazy. What happened? Is the hot tub safe to use? In this article, we will discuss what causes hot tub water to turn cloudy and discuss ways to get your water clear again.

What Makes Hot Tub Water Look Cloudy?

Lack Of Sanitizer

Cloudy hot tub water can be caused by several things. The most common reason being a lack of sanitizer (either chlorine or bromine). Without enough sanitizer in the water, algae and other bacteria begin to grow within the water, causing it to look hazy.

Old, Worn Out Filters

Another common cause of cloudiness in hot tub water is old, worn-out filters. Hot tub filters work by trapping debris in a web of several layers of paper fibres. Over time, these paper fibres will begin to stretch, allowing larger and larger debris to pass through them. This debris will then begin to build up in the water, causing it to look cloudy.

Depending on how often you use the hot tub, you should replace the filters every 12-18 months.

Old Water

Even with perfect filters, ultra-fine particles will build up in the hot tub water over time. To maintain water quality, we recommend draining and filling your hot tub every 3-4 months.

Pump Run Times

If your filter is new and your water is new and you still can't seem to keep the water clear, there might be an issue with your filtration system's run time. Many people only run their hot tubs for a few hours per day in order to save money on running costs. If your filtration system doesn't run long enough, however, the water is never fully cleaned and will look hazy all the time.

We recommend running your hot tub a minimum of 8-12 hours per day to ensure that the water is being properly filtered.

Poor Water Balance

The final reason for hot tub water turning cloudy is poor water balance. Excessively high pH, alkalinity, and/or calcium hardness can cause cloudiness issues.

Troubleshooting Cloudy Hot Tub Water

Water Testing

The first thing to do when your hot tub water turns cloudy is to get your water professionally tested. The first thing you should look for is how much sanitizer is in the water.

If the water has a good bromine/chlorine reading you should then look at its pH and alkalinity levels. If they are high (pH above 8, alkalinity above 180) then there is a chance that they are to blame. The higher pH and alkalinity are, the more likely they are the cause, especially if there is also a lot of calcium or other dissolved solids in the water.


If the water test comes back with a good sanitizer reading and well-balanced water the next thing to look at is your filtration system. When was the last time you changed your water? Is it time to replace the filter? How long do you run your filtration system in a given day?

Is A Hot Tub With Cloudy Water Safe to Use?

If the cloudiness is caused by a lack of sanitizer, avoid using the hot tub until the water has cleared. The bacteria and algae causing the cloudiness in the water can be harmful.

If your water does have a good sanitizer level, however, you can use a hot tub with cloudy water without any real safety concerns.

Treating Cloudy Hot Tub Water

To treat hot tub water made cloudy by a lack of sanitizer, simply keep adding shock to the water until the water maintains a consistent sanitizer level.

If the cloudiness is caused by poor water balance, simply add a pH/alkalinity decreasing chemical until the water comes into balance. It should then clear up on its own within a couple of days.

If your water test results show no obvious cause for the water turning cloudy, then the issue is most likely with the hot tub's filtration system. If the filter is more than 12 months old, replace it. If the water is more than 4 months old, drain and refill the hot tub.

If the hot tub filter and the hot tub water are both still relatively new, try increasing the run time of your hot tub's filtration system to at least 12 hours per day until the problem goes away.

If the cloudiness still persists, try cleaning the filter with a specialized hot tub filter cleaner, or add a couple of caps of water clarifier once per week to help clear out some ultra-fine debris that may be present in your source water.

Wrapping Up

As you can see, cloudy hot tub water can be caused by a number of things. Water balance, filtration issues, and a simple lack of sanitizer can all lead to water clarity issues in hot tubs. Knowing how to spot the difference between them, and getting your water tested, is the only way to clear the water.