How to Maintain a Hot Tub in 3 Steps

Posted by
John Woodard on October 30, 2023

Hot tubs increase blood flow to promote healing, making them a popular socialization and relaxation method. About 5% of households in the United States own a hot tub, and over 70% of polled Americans believe that a spa would increase their quality of life. While hot tubs are designed to help ease worries, murky water can cause concern in spa users and ruin the overall experience. Fortunately, there are simple ways to maintain a hot tub and keep its water crystal clear. In this article, you can find information on what hot tub filters are, how they work, how to select the best filter for your hot tub, and how to manage a spa’s chemicals.

Key takeaways

  • All hot tubs need a filter to keep water clean.
  • Most hot tub filters should be replaced once each year.
  • Look for compatibility and surface area when buying a hot tub filter.
  • Follow a cleaning schedule for your hot tub filter.
  • Test your tub’s water two or three times each week and balance the chemicals when necessary.

Hot tub maintenance steps

To maintain a hot tub, follow these three steps:

  1. Install a hot tub filter and replace it regularly. A spa filter removes dirt, debris, and other contaminants that cloud your water. It prevents these particles from recirculating back into the tub. Most hot tub filters should be replaced once each year.
  2. Clean your hot tub filter. Without regular cleaning, the filter can become clogged. This allows less filter surface area to contact the water as it passes through, slowing filtration down.
  3. Balance your water’s chemicals. Without the correct chemistry, a hot tub is susceptible to microbial contamination, turning the water murky and unpleasant. Hot tub water should be tested two to three times each week.

1.    Install a hot tub filter and replace it regularly.

Does a hot tub need a filter?

Yes, all hot tubs need a filter to remove contaminants that can be harmful to users. People introduce contaminants, such as body oils, lotions, dirt, grime, and chemical products, that cloud a hot tub’s water and make it unsanitary. Hot tub filters trap this debris, ensuring that the water is safe and clear. Without a filter, hot tubs can experience unsightly green water caused by an algae invasion. Unremoved contaminants can also clog a hot tub’s pumps, eventually causing the spa to fail.

The mechanics of a hot tub can also be damaged by other waterborne contaminants, like water hardness. Calcium can scale the insides of a hot tub filter or heater. To reduce the chances of calcium scaling, keep your water’s pH between 7.2 and 7.3 and your water’s alkalinity between 80 and 90 ppm. A pre-filter removes contaminants that compromise the quality of spa water, such as metals, calcium, and other sediments. Pre-filters attach directly to a hose and will filter water as you fill up your hot tub.

hot tub filter replacement

How does a hot tub filter work?

Hot tub filters remove body contaminants such as hair, oils, lotions, and dirt from spa water. They contain a structural plastic core and a filter media that is typically made of polyester. Water circulates through the hot tub, passes through the filter media, and is jetted back into the tub. When water passes through a filter, the folds in the filter media trap the unwanted debris that can damage pumps and cloud the water.

Hot tub filters work best when they are regularly cleaned. Debris can clog a filter’s media and make it less effective at trapping contaminants. Below you can find information on how to best clean your filter.

How to choose the best hot tub filter for your spa

Almost all hot tub cartridge filters are made of polyester, but some are more effective at filtering than others. Surface area is a major factor in a filter’s ability to eliminate debris in a spa. The larger the surface area a filter has, the more contaminants it can catch in the filter media. The Filbur FC-1007, for example, contains a high surface area, so it is more effective at filtering than some of its competitors.

You are limited in the filters you can choose by the filter sizes your hot tub is compatible with. Certain filters are compatible with certain brands of hot tubs, so make sure you purchase one compatible with your specific spa. When replacing a filter, measure the old filter’s length and outside diameter. Once you know the dimensions, you can effectively search for the best filter replacement for your spa.

If your water contains contaminants prior to filling your tub, you will need to consider some prefiltration options. The option you choose should be based on the contaminants present in your water. A spa pre-filter is excellent at removing sediments, metals, and foul odors from water prior to filling a tub, but other options are available. A reverse osmosis system can filter out essentially all contaminants from water. However, hard water can make a reverse osmosis system’s membrane less efficient, so a water softener is a prerequisite to a reverse osmosis system if your water is hard. Well water is more susceptible to contaminants that may damage your spa than city-treated water, so testing your well water is important to know what contaminants need to be filtered.

Learn more: How does a reverse osmosis system work? | What does a water softener do?

Popular Hot Tub Filters

Filbur spa filters boast a high surface area, premium polyester filter media, and a low maintenance design. They also feature antimicrobial end caps that prevent bacteria from impacting the filtration process. Neo-Pure spa filters feature high-strength polyester media that hold their rigidity through multiple cleanings. Below are some popular Filbur and Neo-Pure spa filters, but not all will be compatible with your hot tub. Remember to check what filter types and sizes are compatible with your spa before purchasing.

Filbur FC-1270

The Filbur FC-1270 is compatible with:

  • Harmsco®: H-7487
  • Pleatco: PA100N, PA100N-4
  • Unicel: C-7487
  • Excel Filters: XLS-719
  • Baleen: AK-6052
  • Aladdin: 19902
  • Darlly: 71011
  • Hayward: CX870-XRE

Neo-Pure PS-781-FE

The Neo-Pure PS-781-FE is compatible with:

  • Filbur: FC-1225
  • Baleen: AK-60450
  • Darlly: 70811
  • Excel Filters: XLS-710
  • Pleatco: PA81, PR81-4
  • Unicel: C-7483

Filbur FC-0359

The Filbur FC-0359 is compatible with:

  • Pleatco: PWW50P3
  • Unicel: 6CH-940
  • Excel Filters: XLS-601
  • Baleen: AK-9019
  • Aladdin: 14510
  • Darlly: 60401
  • Rec Factory Warehouse: 378902
  • Waterway Plastics: 817-0050
  • Cyanna Valley Spas (Viking): PWW50
  • Aber Hot Tub: 03FIL1400
  • Millenium Spas: 03FIL1400
  • OEM Part #: 25252
  • Magnum: WY45

Neo-Pure PS-645-BB

The Neo-Pure PS-645-BB is compatible with:

  • Filbur: FC-0359
  • Aladdin: 14510
  • Baleen: AK-9019
  • Darlly: 60401
  • Excel Filters: XLS-601
  • Pleatco: PWW50P3
  • Unicel: 6CH-940

Filbur FC-2971

The Filbur FC-2971 is compatible with:

  • Pleatco: PLBS75
  • Unicel: C-5374
  • Excel Filters: XLS-512
  • Baleen: AK-40081
  • Aladdin: 17540
  • Darlly: 50651
  • Waterway Plastics: 817-0015
  • Leisure Bay: 817-0015, 303433
  • Rec Warehouse: 817-0015, 303433
  • Magnum: DF75

2.    Clean the hot tub filter.

Cleaning your hot tub filter regularly is the best thing you can do to care for your spa. Without proper cleaning, a filter will become oversaturated and not catch contaminants as they pass through. As a result, hot tub users will soak in murky, debris-filled water. Maintaining a regular cleaning schedule will ensure your filter is cleaning as efficiently as possible. Regardless of how well you clean your filter, it will not last forever. When the fibers of a filter media deteriorate, the quality of the filtration is compromised. A filter should be replaced once every 1 to 2 years or sooner if you notice a decline in filtration quality.

Best way to clean a hot tub filter

The best way to clean your hot tub filter involves the following:

  • Weekly rinse
  • Monthly chemical clean
  • Quarterly chemical soak

Weekly rinse

Depending on the frequency a spa is used, a hot tub filter can clog up with hair, dirt, and other debris. Rinsing a hot tub filter weekly allows clean water to pass through freely and guarantees that debris is not reentering the spa.

You can rinse a hot tub filter with a garden hose or faucet. Avoid using a pressure washer or other systems with a high-pressure output as they can damage the filter cartridge. You do not need to use any chemical cleaners in this step as you are simply rinsing debris off the filter. While rinsing, spread each pleat of the filter to maximize cleaning. Once the filter is rinsed, allow it to dry before placing it back into the hot tub.

Monthly chemical clean

Hot tub chemical cleaners come in either a spray bottle or a capped bottle. If your cleaner does not come in a spray bottle, transferring it into a spray bottle will help you easily apply the chemical to the filter. If your cleaner needs to be diluted before use, ensure that you add the appropriate amount of water to the spray bottle beforehand.

To monthly clean your filter, spray it generously with your cleaning solution and let it sit for fifteen minutes. After it has sat, rinse it thoroughly with water exactly how you would weekly rinse your filter. Allow the filter to air dry before placing it back in your spa. If chemical residue is left over on the filter, water can foam up as it passes through and necessitate draining and refilling the hot tub again. The more thoroughly you rinse, the less likely foaming will occur.

Quarterly chemical soak

A chemical soak is needed every time you change your hot tub’s water. If you use your hot tub regularly, you should change out the water every three months. If you do not regularly use your spa, you should change the water at least every four months. When you change a hot tub’s water, you should also clean the tub’s interior. A spa vacuum is an excellent way to maintain a clean environment for the new water.

To soak a hot tub filter, you will need a container large enough to completely submerge the filter and a hot tub filter chemical cleaner. Fill the container with the appropriate amount of water and cleaner as directed on the bottle. Allow the solution to sit for 24 hours. Once it has finished soaking, liberally rinse the filter with water. Allow the filter to air dry before placing it back into your spa. Leftover residue is more likely to stick to the filter in this step than the monthly rinse because of the increased soaking time. Consequently, do not rush through the rinsing process as that could cost you additional time and headache later.

Harmful ways to clean a hot tub filter

Like many spa owners, you may be tempted to opt for a DIY chemical cleaner for your hot tub filter. However, many common cleaners can damage a filter or make spa water unfit for use.

Household cleaners should never be used to clean a hot tub filter. The filter media absorbs these cleaners and will cause foaming problems no matter how much the filter is rinsed.

Bleach is harmful to a filter’s media. Hot tub filters are made of polyester fibers that are not resistant to bleach. Regardless of whether the bleach is diluted or not, it will damage the threads of the filter media and render it ineffective in trapping debris in your hot tub.

Running a hot tub filter through the dishwasher is also extremely harmful to a filter’s fibers. Many DIY guides recommend the dishwasher as an alternative to chemical filter cleaners, but this will cause the filter to need replacing sooner rather than later. Hot tub filters should not be subjected to aggressive water flow, making dishwashers an unsuitable cleaning method.

Ultimately, hot tub filter cleaners are designed specifically to clean the filter media gently with decreased risk of leftover residue. To maximize the life of your filter and keep your spa water clean, you should use cleaner designed for hot tub filters.

3.    Balance the water’s chemicals.

Regularly testing and balancing your hot tub’s chemicals keeps the water clear and safe. Follow a regular testing routine to ensure you test the water consistently.

hot tub jets

What chemicals does a hot tub need?

A vital aspect of spa care is maintaining the water’s chemical balance. Problems such as pH imbalance cause water cloudiness, decreased spa performance, scale buildup, and decreased user comfort.

Types of hot tub chemicals

The most common hot tub chemicals are the following:

  • pH balancers
  • sanitizers
  • spa shock
PH balancers

To maintain pH balance in your hot tub, you need both a pH increaser and a pH decreaser. You will need a pH increaser when the water’s pH dips below 7.2 and a pH decreaser when the pH rises above 7.8. To test your spa’s pH, you can use a spa test strip kit. You should use a test strip on your water 2 to 3 times a week to maintain both your spa’s pH and contamination levels. You will want to balance your hot tub’s pH before you add any other chemicals. Water with an improper pH can render items like sanitizer ineffective.


Chlorine and bromine are popular forms of spa sanitizer. Both are effective at disinfecting water while also preventing cloudiness. Chlorine levels in a hot tub should stay between 1.5 and 3 parts per million (ppm), and bromine levels should remain in the range of 3 to 5 ppm. High levels of both chlorine and bromine can damage the spa cover, fade swimsuits, and even harm the hot tub’s shell.

Mineral sanitizers are an alternative to chlorine and bromine sanitation. They do not possess the odor or damaging properties of chlorine or bromine and are effective at disinfecting water. A downside of mineral sanitizers is that some of their elements are not testable with test strips. Silver ions are a primary component of these sanitizers, and they are not picked up by test strips. To ensure that you are not overloading your water with silver ions, follow the dosage instructions carefully.

Spa shock

Spa shock breaks down organic waste, eliminating odors and clearing up hot tub water in a short amount of time. Shock comes in two forms, chlorine based and chlorine free. Non-chlorine shock is oxygen based, and many spa owners prefer it over chlorine-based shock because of its lack of odor. Non-chlorine shock does not add more sanitizer to the water. Rather, it simply breaks down organic waste by oxidizing the water. Chlorine-based shock, on the other hand, increases sanitization levels in the water while also oxidizing it.

Shock should be used at least once every week. Chlorine-based shock can potentially damage the interior of a hot tub, so caution should be exercised that chlorine levels do not rise too high. Non-chlorine shock, however, cannot harm the interior of a spa, so many spa owners use it generously to ensure that all organic matter is dealt with.

Best hot tub chemical levels

  • The ideal pH for spa water is between 7.2 and 7.8
  • The ideal total alkalinity for a hot tub is between 80 and 120 ppm.
  • The ideal calcium hardness should be between 100 and 250 ppm for acrylic finishes and between 250 and 450 ppm for plaster finishes.
  • The chlorine levels in a spa should read between 1.5 and 3 ppm.
  • The bromine levels in a hot tub should stay between 3 and 5 ppm.

How to test hot tub chemical levels

Spa test kits determine the pH balance, total alkalinity, and total bromine present in your water. Testing your hot tub water is the most common maintenance you need to perform on a spa. Hot tub water should be tested two or three times a week to ensure that pH and chemical balances are satisfactory.

To use spa test strips, such as the Spa Check 3 in 1, dip a test strip into the hot tub and gently stir it around for 5 seconds. Once you remove the strip, shake it to remove excess water and wait 15 seconds for colors to develop. You can compare the colors on the strip to the color chart provided on the bottle. Once you know the pH and chemical balances, you can add the necessary chemicals to the water.


If you have any further questions about how to care for your hot tub water, please don’t hesitate to contact our experts.

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