Spa Filtration: What’s the Best Hot Tub Filters to Use?

They’re one of the most important parts of your hot tub, so choosing the right filter that’s suitable for your pump and fine enough to remove any muck, grime and harmful bacteria is a task that should take a fair bit of thought! 

If you’ve ever tried to replace a hot tub filter, you’ll know that there are loads of options, but some products are simply better at filtering out the nasties than others! 

Our top pick is the Bestway filter cartridge pack. It contains 12 of their excellent type 1 filters featuring durable plastic end caps, large surface area pleats to catch as many particulates as possible, and a thick fabric design that’s suitable for high flow rates of over 300 gallons per hour. 

But what other options are there?

In this guide, we’ll be reviewing.

Seven Of The Best Spa Filters

Before you go shopping for hot tub filters, take time to familiarise yourself with your filtration system and the different types of filters available. From paper filters to ceramic filters, look at the pros and cons of each filtration system individually to ensure that you get the best hot tub filters available. Below, we’ve reviewed the UK’s top 7 filters for spa owners.

Bestway Filter Cartridge Pack VI

Easily our top pick, the Bestway filter pack contains 12 of their excellent 3.1 x 3.5 inch (size 1) hot tub filters, compatible with any 300-330 gallon per hour filter pump.

Bestway is the brand behind the popular Lay-Z-Spa range, so these high-performance cartridge filters will be ideal for most of these models, namely those that use a 1249L per hour circulation pump. 

We love the hard-wearing plastic end caps and thick pleated design that not only provides a large surface area to help trap even minuscule pieces of bacteria and dirt in the filter; but also makes for an easy cleaning process as they can be separated to rinse down! 

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KGC Hot Tub Filter Cartridges

These KGC cartridge filters have been designed with durability in mind, featuring a filtration fabric around 25% thicker than your average paper filter and an open polypropylene flow core that promises to maximise water flow to speed up your hot tub’s filtration process. 

These type 6 replacement filters are 10.6cm wide, 8cm tall, and designed primarily for use with popular Lay Z Spa models such as the Vegas and the Paris, though we’ve found them to be just as effective in any models that use type 6 hot tub filter systems.

We also like that these KGC filters use chlorine-resistant end caps, so they won’t fade or crack when exposed to pool chemicals, making the removal and cleaning process super simple and helping to extend their lifetime! 

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SpaChem PRB35-IN Filter

SpaChem PRB35-IN filters are an excellent choice for hot tubs that see heavy use. Their pleats are made from spun-bonded 100% polyester Reemay filtration fabric, which provides not only incredibly fine filtration but also boasts high tensile strength and great resistance to pool chemicals.

This allows these filters to remain effective for upwards of 1 year, provided that you remove and rinse the cartridges once a month. The acid-free fabric ensures that these filters won’t alter your water chemistry or introduce any of their own contaminants into your hot tub.

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PoolPure Spa Filter

A PoolPure hot tub filter uses a high-tech series of microscopic fibres to provide a larger surface area within the pleats, designed to trap more contaminants than your average filter and release any impurities better when rinsed. 

We’ve found that PoolPure filters can last over a year without suffering cracks or visible wear with chlorine-resistant end caps. The entire filter is made from lead-free and BPA-free materials for maximum safety. 

This PoolPure hot tub filter measures 33.8cm in length, are 12.7cm wide, and are compatible with all three major filtration system manufacturers (Pleatco, Filbur and Unicel), so they’re super easy to find!  

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2 x PWW50 Filters

PWW50 filters are a little more expensive than some of the options on our list, though these Darlly-produced filters are particularly tough, reliable and long-lasting.

PWW50s are made using ultra-durable Reemay filtration fabric, offering uniform thickness across every pleat, with no weak spots or points of vulnerability where tears can begin to form.

These 21cm x 15cm hot tub filters also use trilobal fibres within the pleats, providing extra surface area for collecting dirt and debris. We’ve found that the excellent rigidity of this filter material makes these filters a great choice for pumps with a high flow rate of over 300 gallons per hour.

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MSPA UK Filter Cartridges

These MSPA filters are affordable and use polypropylene pleats, which offer far more durability than the commonly found paper filters you may have used before! 

They come with a protective mesh sock that protects the inside of the filter from large debris and helps the pleats to remain in shape when used with a high flow rate circulation pump.

A filter designed specifically for MSPA, these filters can be directly attached to the water inlet in your spa’s wall and easily removed and cleaned thanks to their screw-in connector.

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Alford & Lynch Hot Tub & Spa Filter

Manufactured with a high-density micro-membrane fabric, we’ve found that these Alford & Lynch filters can easily last over a year. The filter boasts a specially designed core that allows for high flow rates to help keep your hot tub filtration system working at full speed! 

Each filter cartridge contains 45 square feet of washable filtration area, designed to catch everything from hair and body oils to grit, sand and bacteria, with a 30-day money-back guarantee if you’re unhappy with their performance.

>> Check Price At Amazon <<

Why Hot Tub Filters Are So Important

a pair of black and gold filters

We all know how fun hot tubs can be, especially when we’re lucky enough to enjoy them in the company of our closest friends and family, but as with any environment that sees multiple people in close proximity, dirt, grime and harmful bacteria is sure to build up!

Not only can this ruin the serenity of your evening soaks, but poor water cleanliness can easily lead to the contraction of skin rashes, diseases, fevers and (to a lesser extent) the long and tiresome job of draining and scrubbing your hot tub as body oils, dirt and other organic muck begin to clog up your spa’s pumps and jets.

To save you some time in your hot tub maintenance routine and to help you save money on costly spa repairs, even older models make use of some kind of water filtration system. They were designed to rid your hot tub water of harmful contaminants and allow your spa to work perfectly for many years to come! A filter doesnt cost a lot but can save a lot of time and money in the long run!

Finding The Right Replacement Filters

an image of google search page

You’ll need to replace the filter cartridges that keep your hot tub water crystal clear at least once per year to help protect your spa from damage and prevent the risk of bacteria affecting your health. However, if you’re using your hot tub on a daily basis, you may find yourself cleaning and replacing the filter more frequently. So, how do you find the best hot tub filter replacement? 

Filter part numbers

In many cases, the simplest way to ensure that your filter replacement will fit your hot tub is to check for a part number printed onto the casing of your existing filter. 

Part numbers can usually be found on the top and bottom caps of the filter cartridge, and depending on the manufacturer, these codes can be prefaced by a series of letters or consist only of numbers. 

One slightly confusing thing about this method is that otherwise, identical cartridge filters manufactured by different hot tub brands can have alternate part numbers. However, as long as the dimensions are equal, you shouldn’t have issues installing either into your filter system.

Measuring your filters

Measuring your filters is the most reliable way to ensure you’ve got the correct filter replacement, though it can be more time-consuming than finding the filter part number!

The two most important pieces of information you’ll need are your existing filter’s length and outer diameter. These measurements must be the same size as those found on your new filter.

To find the length, measure the cartridge from end cap to end cap, ignoring the handles and attachments that may be on top of the filter’s casing.

To find the diameter, measure across the centre of the filter from edge to edge, though be aware that your measurements here may vary by around 4mm, as filters are known to expand and shrink during use! 

Types Of Filtration Systems

jets pumping water out into the hot tub

There are many types of hot tub filter cartridges available, made by a range of popular brands, but you’ll have to choose the right one for your hot tub model, size, and type. Most cartridges fall into two broad categories: traditional suction side filters and pressure side filters.

Suction side

Most hot tubs make use of a suction side filtration system, which is the industry standard. In a suction side hot tub filter system, a micro-filter is positioned within the hot tub’s ‘skimmer’, where used water is pulled from the surface. 

This water is then passed through the filter basket to remove any large debris and then pumped back through the micro-filter before re-entering the spa via the massage jets.

Suction side hot tub filtration systems are effective and reliable, hence their popularity. But, they’re so commonly installed because they’re relatively inexpensive and easy to fit for manufacturers, which helps keep their production costs down. 

However, these types of cartridge filters aren’t too energy-efficient, with even the most effective suction side systems needing to run continuously for 8 hours a day to filter the hot tub’s water properly. Also, suction side filters only skim the water at the surface, meaning any heavier debris that can sink to the bottom of the pool will need to be removed manually.

Pressure side

Though suction side filters are the standard, that’s not to say there isn’t room for improvement. Some hot tub manufacturers have developed an entirely different system known as pressure side filtration, which differs from a traditional (suction side) filtration system in several ways, such as:

  • The introduction of a floor vacuum in the bottom of the tub.
  • The micro-filter sits on the pump’s outlet (the pressure side of the pump).
  • The micro-filter is situated in a dedicated canister (not in the skimmer).

The most significant change is that this system allows water to flow from the pump to the filter instead of the other way around. 

In a pressure-side hot tub filtration system, the pump draws water in via both the floor vacuum and the skimmer. These systems work together to trap any large pieces of debris, preventing them from passing through and damaging the pump. The water is then cycled through the filtration system before passing through the micro-filter.

Bacteria and smaller pieces of debris are then removed by the filter, with the clean water returning to the hot tub’s main pool via the massage jets. 

Hot tubs fitted with a pressure side filtration system don’t have to be manually cleaned to remove heavy debris. The built-in floor vacuum has that covered. These systems are generally more efficient, being able to filter the average hot tub in as little as 15 minutes.

Other Key Considerations

a hot tub with a hose laying in it

Besides the style of filtration system in your spa, there are several other factors to consider when choosing the right filter. Consider the filter cartridge itself; how easy is it to access and clean? What’s its performance like? 

Think about the surface area; the larger this is, the more debris your filter will be able to catch and remove. Consider filter durability; what material is your spa filter made of? If you want your filter to last as long as possible, go for filters with a reinforced plastic casing.

Also, how many stages of filtration does the filter cartridge have? Two-stage filters do a much better job of removing debris and bacteria in your hot tub water as large pieces of debris are removed first, whilst bacteria, sand, and other particulates are removed in the second stage. 

You should also be sure to take measurements of your current hot tub filter before finding a replacement filter cartridge, including the length, width and outer and inner diameters.


Most experts agree that filter cartridges should be replaced at least once per year, though this should be supplemented by regularly cleaning your filter cartridge once every two weeks.

Microns are a unit of measurement that describes the pore size of a hot tub filter; the smaller the micron rating, the finer the particles that can be removed.

Most hot tub filtration systems work with filters between 1-5 microns. The exact number that your perfect filter will use will depend on the size of the contaminants that need to be removed, with 5-micron filters able to clear sand and dirt and 1-micron filters filtering out most common bacterias. 

Whilst it’s not essential to soak new hot tub filters before installation, doing so won’t harm them. The best time to soak your filters is after three months of use, where an overnight soak in a diluted cleaning solution will help remove built-up grime and extend their life. 

Most standard hot tub filters should last one year at a minimum, and up to 2 years if the filters are cleaned and maintained regularly. Some styles, such as ceramic filters, can last up to 5 years, though it’s more likely that your hot tub will use a cartridge filter system. 

Last Word

a bubbling jacuzzi

That should cover all you need to know when searching for the best hot tub filters to buy in the UK! Remember to accurately measure your existing filter before looking for a replacement, and try to find a part number to make the job even easier! 

Consider whether your hot tub uses a suction or pressure side system, and look for a filter made from a durable material with a large surface area to collect as much debris as possible.

If you want our recommendation, the Bestway filter cartridge pack offers the best value for money with some of the most reliable hot tub filters around. Though provided you remember to regularly maintain and clean your filters, any product in this list should leave you with a happy hot tub!

This page shows the best way to clean a hot tub filter.

John Devlin

Hello, Welcome to my website. I’m John, and I created the InflatableHotTubGuide while researching these spas nearly a decade ago. Since its creation, the site has become the leading UK resource for many models. As a passionate hot tub user, I love to test and explore all the latest machines this industry keeps creating. I hope you find our content helpful.

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