What Causes Cloudy Hot Tub Water?

Wondering why the hot tub’s water looks cloudy and foamy after your recent hot tub party? Before you plan to skip the idea of treating this cloudy hot tub water, read on to know what could have caused it in the first place. We bet that before you reach the end of this guide you will be convinced about getting the cloudy water in your hot tub treated as soon as possible.

Understanding The Concept of Cloudiness

Clouding is a common issue with all hot tub owners and can happen at any time irrespective of how old or new the hot tub is. Even within days of purchasing and using a hot tub, one can experience water foaming and clouding. The key to getting crystal clear hot tub water is to understand what in reality is this haziness and how to tackle it. It is only when you understand the source of the problem that you can solve it from the root.

Water has a certain limit to dissolve substances – air, liquids, and solids. There are several microscopic particles which don’t completely dissolve in water and remain suspended in it. When it comes to hot tub water, Total Dissolved Solids once exceeded beyond limits will end up creating foam and cloudiness. After a specific point, TDS saturates the water completely thus making it appear foamy.

Beyond this level the water’s capacity to accommodate TDS decreases. Hence the TDS has no other option than remain suspended in the water. This is what makes the hot tub water appear cloudy. The more these particles accumulate in the water, the cloudier the water appears. Added to the air bubbles passing through the hot tub’s jets, these particles form foam at the hot tub’s surface.

If TDS is something you’re hearing about for the first time, chances are you must be wondering why doesn’t the filter in your hot tub remove these unwanted particles? The answer to this lies in understanding the chemistry of the particles that contribute towards TDS. These particles are small or microscopic and so they are beyond the capacity of normal hot tub filters. Thus they stay in the water and keep building up until the water is properly treated or entirely replaced.

Factors That Cause Cloudiness In Your Tub

Suspended particles that cause cloudiness in a hot tub’s water can be of many types. They could be dead algae, organic debris, cosmetics, and other insoluble matter. Most of the times these particles are introduced into the water by the hot tub users themselves. Unlike a pool, hot tubs have a lesser ratio of water and space, hence the particles have lesser medium to get dissolved in thereby leading to a build-up.

Broadly classifying the source of these particles, we can say that the cloudiness in your hot tub could be from any or a mix of the following sources:

Human Body:

Most of us are not aware but our body excretions are a huge contributor towards particle build up in our hot tubs. For example, sweat, sebum, dead skin cells, and natural oils produced from the skin can dissolve in the hot tub’s water and remain insoluble after the water’s capacity has been saturated.


If your hot tub is placed outdoors, there are high chances that dirt and dust from the air settle in the water whenever it is in use. If there are trees in the vicinity of your hot tub, there are chances that debris from the trees can fall in the water while the tub is in use. After each use, these particles remain in the water as they are too small to get filtered out.


Body lotions, hair oils, makeup, etc. can also contribute towards cloudiness in a hot tub. These external agents of contamination may seem negligible in their quantity but are a huge factor when it comes to water cloudiness in a hot tub. Adding essential oils to the hot tub can also lead to accumulation of contaminants.

Water Chemistry: 

Improper treatment of the hot tub’s water can also actively contribute towards cloudiness. Chemicals like sanitizers need to be used at their prescribed levels, failing to which can lead to cloudiness. The use of cheap quality hot tub chemicals can also cause the water to become cloudy. If you live in an area where the water hardness is too much, using untreated water in your hot tub could lead to cloudiness. Scale build-up due to calcium and other minerals can make the water too alkaline thus leading to clouding.

Hot Tub Functionality: 

Hot tub filters are put in place to take care of the quality of water. Repeated cloudiness could indicate that the filters are not functioning well and need to be replaced. If the cover of your hot tub is damaged or too old, it might have lost its capacity to protect the water from external contaminants. Keeping the cover on for prolonged periods could also lead to the build-up of microorganisms in the water thus making it look cloudy.

How to Deal With Cloudy Water

The first step while dealing with cloudy water is to test the water with strips. You will need to check the pH and alkaline balance. Keep the sanitizer levels in their optimum to avoid the water from becoming cloudy. Chlorine should be at a level of 3 to 5 ppm while Bromine should be at 4 to 6 ppm. Low levels of sanitizer mean there is not enough fuel to cope up with the accumulation of organic matter in the water.

If the pH is within the recommended range of 7.4 to 7.6, you can go ahead and give the hot tub water a shock. The process of shocking the water oxidizes organic matter thereby dissolving them into gas. Chemical shocks can be done as a non-chlorine shock or using chlorine granules or bromine granules. The most preferred method is a non-chlorine shock as it allows the water to be reused. Typically, a single session of shock can cure the cloudiness, but even after repeated sessions of shocks if the water still looks cloudy, you will need to drain the hot tub completely and refill the water.

Poor water chemistry means smaller particles are getting accumulated. Improper levels of pH and sanitizer should be checked and rectified regularly. Flocculants have the capability to bring together the contaminants so they can be manually removed. Clarifiers also function similarly by removing the contaminants chemically. To minimize the build-up in your hot tub, you can also make sure of purging products like the BioOuster which can free your hot tub from the accumulated gunk while increasing the hot tub’s performance.

Since poor filtration can also cause cloudy water, you might need to consider cleaning or replacing the filter of your hot tub. To further prevent the water from becoming foamy or cloudy, make sure that you schedule the process of cleaning the hot tub’s filter every three to four weeks. Make sure the filter is not clogged or blocked with larger debris as this prevents the filter from functioning properly.

Summarizing the issue of cloudiness, we can say that prevention is always better than cure. Work towards creating a proper maintenance schedule for your hot tub, so that you will experience the unpleasant sight of cloudy water rarely thereby keeping the water in your hot tub crystal clear for longer periods of time.