Pool Filters Explained – Part 4

Part 4: Choosing the Right Pool Filter

Selecting a pool filter isn’t simply a matter of choosing the newest model or the one with the highest price tag. The best filter is the one that suits your pool, your equipment, your maintenance preferences and the way you use your pool.

Many pool owners understandably focus on one feature, such as filtration performance or purchase price, but choosing the right filter requires balancing several factors. A well-matched filtration system will provide years of reliable service, lower running costs and consistently clear water. Conversely, an undersized or poorly matched filter may require more maintenance, increase water consumption and make it more difficult to maintain water quality.

The answers to these questions are often more important than the filter brand itself.

Selecting a pool filter isn’t simply a matter of choosing the newest model or the one with the highest price tag. The best filter is the one that suits your pool, your equipment, your maintenance preferences and the way you use your pool.

Many pool owners understandably focus on one feature, such as filtration performance or purchase price, but choosing the right filter requires balancing several factors. A well-matched filtration system will provide years of reliable service, lower running costs and consistently clear water. Conversely, an undersized or poorly matched filter may require more maintenance, increase water consumption and make it more difficult to maintain water quality.

When assessing a new filter, it’s worth considering the following questions:

• How large is the pool?
• How often is the pool used?
• Is the pool surrounded by trees?
• Do you have a robotic cleaner or in-floor cleaning system?
• Is water conservation important?
• How much routine maintenance are you prepared to perform?
• Is the existing pump correctly matched to the filter?
• Are you planning future equipment upgrades such as heating or automation?

The answers to these questions are often more important than the filter brand itself.

Pool Size Matters

Perhaps the biggest mistake people make is selecting a filter based only on the pool’s volume.

While the amount of water in the pool is certainly important, it’s only one part of the equation.

A larger family pool with heavy daily use, nearby trees and frequent entertaining may place far greater demands on the filtration system than a larger pool that is covered most of the time and used only occasionally.

The goal is not simply to circulate all the water in the pool—it is to provide enough filtration capacity to comfortably handle the expected contaminant load throughout the swimming season.

Whenever practical, choosing a slightly larger filter than the minimum recommended size is often a worthwhile investment.

A larger filter generally operates at lower pressure, requires less frequent cleaning and may provide better long-term performance.

Technician’s Tip
If you’re deciding between two correctly matched filter sizes, the larger filter is often the better long-term investment. Larger filters typically operate with lower resistance, require less frequent cleaning and place less stress on the circulation system. While the upfront cost may be slightly higher, the additional filtration capacity can make ongoing maintenance easier.

Matching the Filter to the Pump

A pool filter does not operate in isolation.

It forms part of a hydraulic system that includes the pump, pipework, valves, heaters, chlorinators and return inlets.

For this reason, the pump and filter should always be selected together.

An oversized pump connected to a small filter may force water through the filter faster than intended, reducing filtration efficiency and increasing operating pressure.

Conversely, a very small pump connected to an excessively large filter may result in longer turnover times and reduced circulation in some areas of the pool.

The best systems are those where the pump flow rate and filter capacity have been carefully matched by design.

Modern variable-speed pumps make this easier because they allow water flow to be adjusted to suit different operating conditions while significantly reducing electricity consumption.

Consider Your Surroundings

The environment around your pool can have a major influence on filter selection.

For example:

Pools surrounded by trees

Leaves, blossoms, pollen and organic debris can place significant demands on the filtration system.

In these situations, many pool owners appreciate the simple maintenance of a media filter, particularly where frequent cleaning would otherwise be required.

Dust-prone environments

Pools in rural areas or near construction sites often experience high levels of fine dust.

Excellent circulation and adequate filtration capacity become particularly important.

Indoor pools

Indoor pools generally experience much lower debris loads than outdoor pools.

As a result, filtration demands are often reduced, although water chemistry and ventilation become more important considerations.

Water Conservation

Australia’s climate means water conservation remains an important consideration for many households.

This is one reason cartridge filters have become increasingly popular.

Unlike media filters, cartridge filters are cleaned without backwashing, meaning there is very little water loss during routine maintenance.

Media filters, while still highly efficient, require periodic backwashing to remove accumulated debris.

Although the volume varies depending on the installation, regular backwashing inevitably results in some water and chemical loss.

This does not necessarily make cartridge filters the better choice—it simply means water usage should be considered alongside maintenance preferences and overall operating costs.

Maintenance Preferences

One of the biggest practical differences between filter types is how they are maintained.

Some pool owners prefer quick, infrequent backwashing.

Others are happy to remove and clean cartridge elements periodically in exchange for lower water consumption.

Neither approach is inherently better.

It simply depends on which maintenance routine best suits your lifestyle.

Future Equipment Upgrades

Many people purchase a filter intending to keep it for ten years or more.

During that time, additional equipment is often added.

When planning a new filtration system, it is worth considering whether these future additions may alter circulation requirements or increase overall system complexity.

Designing with future upgrades in mind can help avoid unnecessary equipment replacement later.

Should You Replace the Filter or Upgrade It?

Sometimes the best option is not simply replacing an old filter with the same model.

If the existing filter has always struggled to keep the pool clear, it may be worth reviewing whether the original equipment was correctly sized.

Modern filtration systems are often more efficient than equipment installed twenty years ago.

Upgrading to a larger filter, replacing ageing pipework or installing a variable-speed pump at the same time may significantly improve overall system performance.

Technician’s Perspective
One of the most rewarding parts of our work is seeing the difference a correctly designed filtration system can make. Many pools we inspect don’t actually have faulty equipment—they simply have equipment that is undersized, poorly matched or no longer appropriate for the way the pool is used today. Careful equipment selection often delivers better results than simply replacing individual components.

Choosing a Quality Manufacturer

While this guide has intentionally focused on filtration principles rather than specific brands, manufacturer quality should not be overlooked.

A well-designed filter from an established manufacturer is more likely to provide:

• Reliable hydraulic performance.
• Durable construction materials.
• Readily available spare parts.
• Comprehensive warranty support.
• Ongoing technical assistance.
• Compliance with relevant Australian standards.

These factors often become far more important over the life of the filter than small differences in advertised filtration performance.

Looking Ahead

In the final part of this guide, we’ll cover the practical side of filter ownership. We’ll explain how to maintain different filter types, recognise common problems before they become expensive repairs, troubleshoot cloudy water, understand pressure gauge readings, answer frequently asked questions, and finish with a concise summary to help pool owners choose the filtration system that’s right for them.

Disclaimer: The information provided in this article is intended as a general guide to help pool owners better understand swimming pool equipment and maintenance. While every effort has been made to ensure the information is accurate at the time of publication, it should not be relied upon as specific technical or professional advice. Every swimming pool is different. Factors such as pool size, construction, equipment configuration, hydraulic design, water chemistry, environmental conditions and how the pool is used can all influence the most appropriate solution. Recommendations that are suitable for one pool may not be appropriate for another. Before purchasing, modifying or replacing pool equipment, or making significant changes to your pool’s operation or water chemistry, we recommend seeking advice from a qualified pool professional who can assess your individual circumstances.

If you would like independent advice on selecting the right filtration system, diagnosing a pool problem or optimising your pool equipment, the team at SplashCraft is always happy to help.