One of the most memorable hot tub water care questions this author has ever received involved the topic of filters. Years later, the conversation is just as relevant today partially because it not only highlighted the importance of proper filter care, but also the integral role they play in helping keep hot tub water clean and the jets flowing at the proper water pressure.

The call came from a dog owner who adored her pet so much she would let it use her hot tub almost as much as she did. This practice is not necessarily rare for pet owners who own pools; however, sharing 1500 L (396 gal) of relatively confined water with ‘man’s best friend’ had never crossed this author’s mind.

The customer, who had only owned her hot tub for a month, called to ask why the jets in her hot tub were not providing the same hydrotherapy she had come to enjoy during the first couple of weeks of hot tub ownership. She also mentioned the water was cloudier than she desired.

The slow water flow issue immediately begged the question, “When was the last time she took her filter out and rinsed it?”

Her response was equally informative: “What filter?”

As it turned out, she did not know there was a filter in her hot tub that worked to assist in keeping the water clean, nor was she aware that it should be removed and rinsed regularly. With so many chemical options available for hot tub owners to concern themselves with, the filter is often overlooked. There are likely many more scenarios such as this one; therefore, it is important to educate customers about hot tub water care and the importance of filter maintenance. Both go hand-in-hand in keeping hot tub water clean and clear, as well as experiencing hydrotherapy to the fullest.

The importance of keeping hot tub filters clean

Clean water is necessary to experience the full enjoyment of a hot tub. This means chemically balancing the water and checking the sanitizer level. For some hot tub owners; however, this is where it stops. If everything checks out, they think they are ready to go.

However, this is not the case if the filter has been disregarded. In fact, filters are one of the most important parts of the hot tub system. When bathers use the hot tub, particulates such as sand, dust, lint from clothing, and soils from surrounding surfaces are often carried into the water. These particulates need to be removed to ensure water clarity. This is where the filter comes into play.

Remove the filter regularly

If the hot tub is used frequently, the filter should be removed and cleaned weekly. If it only sees occasional use, filter maintenance should be performed every two weeks. In doing so, service professionals should use a high-pressure, fresh-water stream to rinse the filter. In most cases, the color of the filter will change as the captured dirt is washed out.

If left ignored, the hot tub filter will eventually become clogged with particulate (e.g. dirt, organics, and even dog hair). Some debris can be so minute that it cannot be removed simply by washing or rinsing. This will result in a lower flow rate, as well as place a larger workload on the pump to circulate the water.

The hot tub filter also does a great job of reducing foam caused by residual laundry soap from bathing suits. If this type of foaming is experienced, the filter should be rinsed more than once a week and the soapy bubbles should dissipate naturally and at a quicker rate—all without the need to introduce more chemicals such as a foam decreaser.

Other types of foam are the result of organics (e.g. body oils, sweat, hair, food/drinks, dust, leaves, rain, etc.) that are introduced into the hot tub water. The filter, along with the addition of a water conditioner, can also reduce this type of foaming.

How to maintain a hot tub filter

Service professionals should advise hot tub owners to get into the habit of removing their filter on a weekly basis to give it a fresh water rinse. In warm climates, this can be accomplished with a garden hose. If it is cold outside, the filter can be rinsed in a utility sink or bathtub inside the home.

The hot tub owner can also use aftermarket hose attachments (e.g. comb-like spray nozzles) that are designed to help rinse the filter pleats. This simple step will go a long way toward keeping the filter cleaner, as well as prolong its life.

There are also several products on the market to give a filter a deeper, chemical rinse. These products work adequately to remove loose particulates. Some require an overnight enzyme soak, while others involve placing the filter in the water, in the center of the hot tub, when performing a plumbing line purge. The scouring agents used to clean out the lines beneath the hot tub are also strong enough to clean the filter pleats. When using any one of these chemical cleaning methods, ensure the customer’s filter is thoroughly rinsed before reinstalling it in the hot tub’s filter compartment.

The cleaning methods outlined above work for most paper-media filters. There are ceramic filters available as well. If a hot tub is equipped with one of these types of filters, which are typically more expensive, the service technician should check the manufacturer’s recommendations before cleaning. In many cases, the filter’s ceramic plates become coated with slime, which can be rinsed or wiped off and replaced.

Finally, there are two home remedy methods that some hot tub owners have used over the years to clean their filters—dishwashers and bleach. If the homeowner asks about these types of cleaning procedures, this author would only recommend the first option should the homeowner desire. However, before running the filter through a dishwasher cycle, advise the homeowner to make sure the filter is dishwasher safe as per the manufacturer.

As for bleach, this is a popular mistake many make when cleaning filters. Sure, bleach does a great job of making the filter look white again, but what happens is the paper media becomes corroded by the harsh chemical and, as a result, the filter life is reduced. The idea behind cleaning a hot tub filter is to ensure it is working properly, not look whiter. The filter is going to get dirty, as that is its job.

When is a new filter required?

When a filter becomes clogged beyond the point of rinsing, or if the media has eroded, a service professional should advise the hot tub owner that it is time to purchase a replacement. When replacing a filter—whether performed by a service professional or the homeowner—it is important to reference the hot tub’s operating manual to ensure the proper media is selected and is sized correctly. A good tip is to measure the existing filter first.

There are many different options for filters, including the size of particulates that they remove (microscopic differences between tiny and super small), which is why it is important to compare the dimensions of filters with specified data in the operator’s manual.

Hot tub filters need care and replacement just like the filters used on a household furnace and vehicle.

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This article was written by Colin Taylor, B.Sc. and originally appeared on Pool & Spa Marketing [link].