05 Oct Choosing the Right Pool Filter for Your Pool
The right pool filter depends on your pool size, how much maintenance you want to do, and the water quality you need to achieve. Sand filters suit most residential pools and are straightforward to maintain; glass media improves on sand by capturing finer particles; cartridge filters eliminate backwashing entirely. Understanding these differences before you speak to a technician helps you make a confident, practical decision.
What does a pool filter actually do?
A pool filter removes suspended particles from the water before they cause cloudiness, algae growth or a risk to swimmers’ health. Without effective filtration, even a well balanced pool will turn cloudy and eventually green, because chemical treatment alone cannot remove physical debris, body oils, sunscreen or fine organic matter.
Sand filters trap particles in the 20 to 100 micron range, catching dirt, leaves, grass, hair, body oils, sunscreen and bacteria. That 20 to 100 micron window is the baseline for comparing filter types: glass media captures particles finer than the lower end of that range, which is why it improves on sand for clarity and chemical efficiency, while cartridge elements can also capture particles at the finer end of the scale depending on the element rating. When the filter type or size is not matched to your pool’s demands, smaller particles pass straight through, your pump works harder, and water quality suffers regardless of how much chemical you add.
Which filter types are available for residential pools?
The three main filter types used in residential and commercial pools are sand filters, cartridge filters and glass media filters, each with different filtration efficiency, maintenance requirements and running costs.
- Sand filters use a bed of filter sand inside a round or bottle shaped tank with a multiport valve. Settings include filter, backwash, rinse, waste, circulation and closed, giving you control over routine cleaning cycles. They are durable, low maintenance and well suited to most Melbourne residential pools.
- Cartridge filters use a pleated cartridge element that captures particles without requiring backwashing. The cartridge is periodically removed and hosed clean, and no backwash water is wasted in the process. They are a practical choice where water conservation is a priority.
- Glass media filters use recycled crushed glass in place of sand inside a standard filter housing. Because glass media captures particles finer than the 20 to 100 micron range that sand handles, it can reduce chemical demand and improve water clarity noticeably. For pool owners who already have a sand filter, switching to glass media is often a cost effective upgrade without replacing the whole unit.
Aquatech Pool and Spa Solutions services and installs all three filter types across Melbourne. Aquatech’s pool filters page covers the options available for residential and commercial pools throughout the service area.
How do I know what filter size my pool needs?
Filter sizing is based on your pool’s water volume and the flow rate your pump produces; an undersized filter restricts flow, strains the pump and leaves fine particles in the water.
As a general rule of thumb across the industry, a filter’s flow rate rating should match or exceed the output of your pump at its operating speed. A common mistake is pairing a high flow variable speed pump with a filter that was sized for an older, smaller single speed unit, so confirming the match before purchasing avoids unnecessary replumbing or performance problems down the track.
Is a sand filter or cartridge filter easier to maintain?
Sand and glass media filters are maintained through backwashing, a process that takes a few minutes by switching the multiport valve setting; cartridge filters require the element to be removed and hosed down, with no water lost to a backwash cycle at all.
Sand and glass media filters suit pool owners who prefer a quick valve turn to clean the system and do not want to handle filter components directly. Cartridge filters appeal to owners who want to minimise water loss, which is a practical consideration in areas subject to water restrictions. The trade off is that a cartridge element has a finite service life and must be replaced when it deteriorates, making it an ongoing consumable cost to factor into your decision.
Does pool usage or pool type change which filter I should choose?
Yes, a heavily used pool or a commercial pool with high bather loads needs a filter with greater capacity and straightforward servicing, because fine debris and organic load will overwhelm an undersized unit quickly.
For a lightly used backyard pool in a relatively clean environment, a correctly sized sand or cartridge filter performs reliably. Pools surrounded by established trees or gardens carry a higher debris load and benefit from a larger filter housing or glass media to reduce intervention frequency. Commercial pools face stricter water quality standards and typically require larger, high flow filter systems matched to their bather load and turnover requirements.
When should I replace the filter media rather than the whole filter?
Filter media, whether sand or glass, loses its filtration efficiency over time as particles pack the bed and the media surface becomes coated; replacing the media restores performance without replacing the entire filter housing.
A filter that consistently returns cloudy water after backwashing, or that requires unusually frequent backwash cycles, often needs a media change rather than a new unit. If the tank itself is cracked, the multiport valve is failing, or the internal laterals are broken, replacement of the whole filter is the more practical option. Where equipment is assessed before any recommendation is made, the general principle in pool servicing is to repair or replace worn components first, and only recommend a full replacement when repair is no longer practical or cost effective.
What questions should I ask before buying a pool filter?
Before committing to a filter, confirm it is correctly rated for your pump’s flow, that the housing is large enough for your pool volume, and that replacement media or cartridges are readily available locally.
- Is the filter flow rate matched to my current pump output, and will it still suit the pump if I upgrade to a variable speed unit later?
- Does the filter housing suit sand, glass media or a cartridge element, and can the media be upgraded later without replacing the tank?
- What is the ongoing cost of cartridge replacement or media changes over the expected life of the filter?
- Does the brand offer reliable local service support? Astral filtration systems, for example, are built from non-corrosive materials, are low maintenance and are designed to save on large quantities of water.
- If the filter will be backwashed regularly, is the waste outlet positioned so backwash water drains safely and legally under local council requirements?
Sources
This article draws on the following pages.