Causes of Cloudy, Foamy Hot Tub Water & How to Fix It

Cloudy hot tub water is one of the most common issues for spa owners. With regular use, hot tub water can turn from crystal clear to a hazy grey very quickly. Cloudy water is usually caused by suspended particles in the water that are too small get picked up by your filters. Along with cloudy water, foamy water can persist. An easy fix for foam, is Hydropool North West's Foam Away product. Read on for more information on how to solve and prevent cloudy, foamy water in the future.


The short and simple answer is no. For safety reasons, the water in your hot tub should be clean and sanitary. Cloudy spa water indicates something is wrong. It could be excess bacteria or a chemical imbalance. You should rectify the situation before using the spa or hot tub again.


A common cause of cloudy hot tub water is heavy usage, without proper cleaning. The more you use your hot tub, the more often you have to deep clean the hot tub water. Our Self-Cleaning Hot Tub Range with HydroClear Pure Water System; uses UV and Ozone sanitisation, which alleviates the need to deep clean so often. The Self-Cleaning & HydroClear water system also reduces the amount of sanitising chemicals needed by 50%, making your spa easier to care for and maintain.

Other Causes of Cloudy/Foamy Water:

POLLUTANTS IN THE AIR OR WATER: Many pollutants and organic debris such as pollen, dust, and insects float around in the air. Eventually, these are going to find their way into your hot tub water. Borehole water, or water directly from the house can have metals that will cloud water.

BACTERIA AND ALGAE: The warm water in your hot tub is a perfect breeding ground for algae and bacteria. Not only can bacteria growth cause cloudy or unclear water, bacterial growth can also cause severe skin irritations. If your hot tub is chemically balanced, this wouldn't be an issue. Water safety is in your hands!

CHEMICAL IMBALANCE: To ensure the clarity of your hot tub water, you must maintain the correct water balance. Do this by using the right hot tub chemicals to balance the water chemistry. Keeping an ideal sanitiser level is a cornerstone of basic hot tub chemistry and will help maintain water that is safe, clean and clear. Unbalanced water can result in staining, scale build up and green, foamy, or cloudy water. If you have a green water problem check out this article!

POORLY FUNCTIONING FILTERING SYSTEM: If your hot tub filtering system is old, poorly fitted, not working correctly or is overused, the filters will not function efficiently and remove particles. An ineffective hot tub filter will eventually cause cloudy water. Hydropool North West is available to send an engineer to sort out any issues with the functionality of your Hot Tub or Swim Spa.

SKINCARE PRODUCTS: When you use a hot tub, substances on your body will end up in the water. Products such as body oils, makeup, hair conditioners, and lotions affect the water quality. Dead skin cells can also be a problem and can lead to foaming in the water. Skincare Products are the number one cause of Foamy Water.

POOR WATER CARE: A poor maintenance schedule could lead to cloudy water. Make sure you check and balance the hot tub water regularly, using chemicals specifically designed for hot tub use. Using incorrect or cheap chemicals can also lead to foam forming in the water. Drain and refill your spa as per the manufacturer's guidelines - we recommend every 3-4 months with a Hydropool Self Cleaning Hot Tub.

AIR IN THE SYSTEM: Tiny bubbles or small air particles can make spa water look cloudy or foamy on the surface. For a first time user this can often be worrying, but this is normal, and part of your hydrotherapy experience - once your jets have turned off, you should notice your water clarity returns to normal after about 10 minutes.

POOR CIRCULATION: Allowing your hot tub water to sit for long periods, inactive, could lead to it becoming cloudy. We recommend setting up multiple, shorter filtration cycles throughout the day, rather than one long period, so your pumps kick in more often and water doesn't sit for too long.


Sometimes you will have to try a few of theses options until you reach the desired result:

1. Check Ph and Alkalinity Levels: You can test your water using a test strip and drop-style kits. The core levels should be as follows:

  • Ph levels - 7.4 - 7.6

  • Total Alkalinity - 100 - 150 ppm

  • Sanitiser levels - Chlorine - 3 - 5 ppm OR Bromine 4 - 6 ppm

2. Shock Treatment: If it is minerals making your water cloudy, you may need to shock your hot tub water. If your hot tub uses a chlorine sanitiser or other minerals, you should use powdered or tablet chlorine or a non-chlorine shock.

If your hot tub uses bromine sanitisers, try a non-chlorine shock or powdered/tablet bromine. such as AquaSparkle Non Chlorine Shock. This product will also help those on bromine to activate the bromine and help it work more effectively. Non chlorine shock treatments are usually the preferred treatment method. When you add sanitiser to shock hot tub water, it eliminates organic matter by turning it into a gas. . To prevent your hot tub water from going cloudy, treat it with 30g (1 capful) of granular sanitiser to ensure the level rises back to the safe range. Add sanitiser as required based on your test strip results. On average most people add sanitiser 2-3 times per week. Remember to shut off the air valves when adding chemicals.

3. Check and Clean the Filters: Substances such as dead algae can build up in your filters and upset the water clarity. Your Hot Tub OR Swim Spa Filter requires regular cleaning. Check them weekly, rinse them regularly; a blocked filter means that it isn't doing its job properly. Use filter cleaner to wash them at least once a month to remove oils and greases. For our personal hot tub, we soak our filters for up to (Insert number), then rinse them off. When properly maintained, a filter can last 6-12 months.

4. Use Water Clarifier: A clarifier coagulates and brings together all the minute particles your hot tub filter fails to trap. The filter can then trap the new larger particles and remove them. Take care not to use too much clarifier because it could make the problem worse.


Prevention is the best way to stop cloudy Hot Tub/Swim Spa water from occurring.

  • Always shower before jumping in the hot tub. This means rinsing yourself off in clean water and not using any soap. If users wear swimming costumes, this can dirty the water. To avoid this, rinse them in warm water and avoid using detergents. Overall, you want to reduce the amount of body oils, detergents, and any other (not spa safe) soaps/lotions.

  • A clean filter keeps the hot tub's water clear and clean by preventing scale or any slimy substance from building up. Thus, always follow a regular maintenance schedule that includes checking the filter, rinsing the filter every week, cleaning the water filter every month, and replacing it whenever necessary. Most filters should last around twelve months before you need to replace them. But, if you notice tears or filter pleats stuck together, it makes sense to replace the filter straight away. Otherwise, it will be ineffective in trapping particles and contaminants. Hydropool North West provides scheduled cleanings and maintenance with various options and prices to take the worry off our customers.

  • You should also check hot tub chemical levels regularly. You must monitor alkalinity, pH and sanitiser levels. If necessary, adjust them. You can use chemicals such as alkalinity or pH balance. By being proactive and balancing your chemicals properly you reduce the risk of cloudy water.

  • Every four months, use hot tub flush before draining the water from the hot tub, to prevent biofilm build up inside the pipework. Once empty hose down the acrylic shell and jets, and then refill it. Hydropool North West provides flushing in our service packages.

  • It might seem obvious, but using a Hot Tub Cover when the spa is not in use will prevent airborne debris, particles and other contaminants from falling into the water. It also keeps the heat locked in, using less energy. Hydropool North West supplies a cover with purchase of any Hot Tub or constant current Swim Spa.

*All Spas Do Differ, so this article must be taken as advice, please refer to your manufacturer's manual and guidelines for further information!