How to Choose the Best Pool Filter for Your Pool

Choosing the best pool filter for your pool is a bigger decision than most owners realise. The filter does half the work of keeping your pool clear — chemistry is the other half — and a mismatched filter makes every other part of pool maintenance harder. This guide walks through sand, cartridge and DE filters, real pricing in 2026, and how to pick the right size and type for your situation.

The three pool filter types

Sand filters

Sand filters force water through a bed of graded silica sand (or glass media) that traps debris. They’re the oldest and most common filter type in Australia, and they’re famously robust.

• Cost 2026: $700 to $1,800 supplied and installed
• Media replacement: Every 5 to 7 years, $150 to $300
• Maintenance: Weekly backwash and once-a-year media check
• Filtration level: Down to about 30 microns (or 15 microns with glass media)
• Pros: Cheap, robust, easy to maintain, handles algae well
• Cons: Less fine filtration than cartridge or DE, backwash wastes water

Cartridge filters

Cartridge filters use replaceable fabric cartridges (usually polyester) with pleated surfaces that trap debris as water passes through. No backwashing required.

• Cost 2026: $900 to $2,200 supplied and installed
• Cartridge replacement: Every 2 to 4 years, $100 to $300 per cartridge
• Maintenance: Hose clean every 2 to 4 weeks
• Filtration level: Down to about 20 microns
• Pros: Better filtration than sand, no water waste, simple
• Cons: More maintenance attention than sand, cartridges need replacing

DE (diatomaceous earth) filters

DE filters use fossilised diatom powder as the filtration medium, coated onto internal grids. They provide the finest filtration available in residential pools.

• Cost 2026: $1,500 to $3,500 supplied and installed
• DE powder replacement: After each backwash, $20 to $50
• Maintenance: Backwash as needed, full clean annually
• Filtration level: Down to 3 to 5 microns — virtually polished
• Pros: Absolute best filtration, crystal-clear water
• Cons: Most expensive, more complex, DE handling requirements

Which filter is right for your pool

Go sand if:

• You want simple, cheap and robust
• You’re on a budget
• You have algae issues that need aggressive backwashing
• You don’t mind water use for backwashing

Go cartridge if:

• You want better filtration than sand
• You’re on tank water or water restrictions (no backwash)
• You don’t mind hose-cleaning cartridges periodically
• You want the cleanest water for less cost than DE

Go DE if:

• You want absolute premium filtration
• You have allergies or sensitivity to fine particles
• You’re willing to pay more upfront and spend time on maintenance
• You have a high-end pool and it matters to you

Sizing: the mistake most people make

Filter sizing is where 80% of filtration problems come from. Most Australian residential pools are sold with filters sized to match the pump, which results in under-sized filters for the pool volume.

Here’s the rule of thumb: pick a filter that’s at least 1.5x larger than the minimum rated size for your pool volume. Over-sizing the filter does three things:

• Extends cleaning interval (less frequent backwashing or cartridge cleaning)
• Increases filter life (less strain per cycle)
• Improves water clarity (slower flow through more media)

Undersized filters need constant attention, clog quickly, and struggle to keep water clear during summer or after storms.

Filter maintenance: the stuff nobody tells you

Sand filter tips

• Don’t over-backwash — 60 seconds is usually enough
• Don’t backwash unless pressure has risen 7 to 10 psi above clean baseline
• Replace sand every 5 to 7 years — old sand loses effectiveness
• Consider switching to glass media for finer filtration

Cartridge filter tips

• Hose clean monthly during summer, every 6 weeks in winter
• Soak cartridges in filter cleaning solution every 6 months
• Replace cartridges every 2 to 4 years even if they look OK
• Never clean with bleach — it damages the fabric

DE filter tips

• Always re-coat with fresh DE after backwash
• Full tear-down and clean annually
• Watch for damaged grids — they mean DE gets into the pool

When to replace vs repair

Filter tanks typically last 15 to 20 years. Internal components (valves, manifolds, laterals, grids) last 8 to 15 years and are replaceable. If your filter tank is sound and only internal components are failing, repair is usually cheaper than replacement.

If the tank is cracked, the multiport valve is beyond repair, or you’re upgrading filter type entirely, full replacement is the way to go.

Coordinating with other pool work

If you’re resurfacing your pool, it’s the ideal time to check and upgrade your filter. The pool is offline, you’re already disrupting the backyard, and replacing an aged filter adds hours (not days) to the work. Read our complete maintenance guide or pool pump replacement cost article for broader equipment context.

Our pool equipment service covers filter supply and installation. For resurfacing pricing, check our cost guide or use the cost estimator.

Unsure which filter is right for your pool? Contact us or call 1800 724 683. We’ll look at your pool volume, usage patterns, and water source and recommend the best pool filter for your specific situation.