Pool Filter Buying Guide
Pool Filter Buying Guide
Sand vs Cartridge · Magna-Flo & Astral · All models matched to pool size
Clean, clear water starts with the right filter.
Your pool filter is the workhorse of your filtration system — removing dirt, debris, algae spores and fine particles every time your pump runs. Choosing the right type and size makes a real difference to water clarity, how often you need to maintain it, and how long your equipment lasts. This guide covers everything you need to know, plus every filter we stock at Drive In Pool & Spa Warehouse.
How does a pool filter work?
Pool water is drawn in by your pump and pushed through the filter housing, where a filtration medium — either sand or a pleated cartridge — traps particles as small as 10–40 microns (particles invisible to the naked eye). The cleaned water then flows back through your chlorinator and returns to the pool.
Over time the filtration medium collects debris and becomes less effective. Sand filters are cleaned by backwashing — reversing the water flow to flush waste to drain. Cartridge filters are cleaned by removing the cartridge and hosing it down. A correctly sized filter typically only needs cleaning every 4–8 weeks under normal conditions.
Types of Pool Filters
Sand Filter — Top Mount
The most popular pool filter in Australia. The multiport valve sits on top of the tank for easy access. Backwash by turning the valve to the backwash position and running the pump for 2 minutes. Simple, reliable and the most common configuration for residential pools. All Magna-Flo top mount models include a 40mm or 50mm multiport valve.
Sand Filter — Side Mount
Same filtration performance as a top mount, but the multiport valve is positioned on the side of the tank. Ideal when your equipment bay has limited overhead clearance — common in compact pump installations or covered equipment areas. Magna-Flo side mount models are available in 21", 25" and 28" diameters.
Cartridge Filter
Uses a pleated polyester cartridge instead of sand — filters down to approximately 10–15 microns, finer than sand. No backwashing required; simply remove and hose the cartridge clean. Uses significantly less water than sand filter backwashing — ideal in areas with water restrictions. Astral Hurlcon ZX is Australia's most popular cartridge filter range.
Sand Filter vs Cartridge Filter — Which is Right for You?
Both types keep your pool water clean and clear. The right choice depends on your pool size, water availability, and how hands-on you want to be with maintenance.
Sand Filter (Magna-Flo)
- Filters to 20–40 microns
- Backwash cleaning — 2 min process
- Uses water to backwash (to drain)
- Sand lasts 5–7 years
- Lower upfront cost
- Best for larger pools and higher debris loads
- Multiport valve gives 6 operating positions
Cartridge Filter (Astral Hurlcon ZX)
- Filters to 10–15 microns — finer clarity
- Remove & hose — no backwash needed
- Water efficient — great for restrictions
- Cartridge lasts 2–3 years
- No multiport valve needed
- Best for smaller pools, water-restricted areas
- More compact housing
Which Filter for Your Pool Size?
Filter size is measured by tank diameter. Larger diameter = more filtration media = longer between cleans. Always size up if in doubt.
Recommended Models
- Magna-Flo 21" Side MountSand · 40mm
- Astral Hurlcon ZX75CCartridge
- Astral Hurlcon ZX100CCartridge
Compact pools, plunge pools, above ground pools.
Recommended Models
- Magna-Flo 25" Top MountSand · 40mm
- Magna-Flo 21" Side MountSand · 40mm
- Magna-Flo 25" Side MountSand · 40mm
- Astral Hurlcon ZX150CCartridge
Most common size for standard suburban in-ground pools.
Recommended Models
- Magna-Flo 25" Top MountSand · 40mm
- Magna-Flo 28" Side MountSand · 50mm
- Astral Hurlcon ZX200CCartridge
Larger family pools — size up to reduce backwash frequency.
Recommended Models
- Magna-Flo 28" Side MountSand · 50mm
- Magna-Flo 28" Top MountSand · 50mm
Large entertaining pools. Contact our team for flow rate advice.
Brands We Stock
Magna-Flo is a dedicated pool filtration brand offering an excellent range of top and side mount sand filters at competitive prices. All Magna-Flo filters include a quality multiport valve and are designed for straightforward installation and low maintenance. A reliable, great-value choice for Australian pool owners of all pool sizes.
Top Mount Range
| Model | Diameter | Valve | Pool Size | Price |
|---|---|---|---|---|
| Top Mount 25" | 25 inch | 40mm Multiport | Up to 55,000L | $700 |
Side Mount Range
| Model | Diameter | Valve | Pool Size | Price |
|---|---|---|---|---|
| Side Mount 21" | 21 inch | 40mm Multiport | Up to 40,000L | $700 |
| Side Mount 25" | 25 inch | 40mm Multiport | Up to 55,000L | $850 |
| Side Mount 28" | 28 inch | 50mm Multiport | Up to 100,000L | $1,200 |
Astral's Hurlcon ZX is Australia's most trusted cartridge filter series. The pleated polyester cartridges filter to approximately 10–15 microns — finer than sand — delivering exceptional water clarity. No backwashing means no water waste and no multiport valve needed. Cartridges are simply removed and hosed clean every 4–8 weeks. Ideal for pools in water-restricted areas or owners who want a low-maintenance, compact filtration setup.
Hurlcon ZX Series
| Model | Cartridge Area | Pool Size |
|---|---|---|
| Hurlcon ZX75C | 0.75 m² | Up to 30,000L |
| Hurlcon ZX100C | 1.0 m² | Up to 40,000L |
| Hurlcon ZX150C | 1.5 m² | Up to 55,000L |
| Hurlcon ZX200C | 2.0 m² | Up to 80,000L |
Key Things to Consider
A larger filter runs at lower pressure, needs cleaning less often and lasts longer. Spending a little more on a bigger tank always pays off over the life of the filter.
Your filter must be rated to handle your pump's maximum flow rate (m³/hr). An undersized filter creates excessive pressure and reduces filtration effectiveness.
If your equipment bay has low overhead clearance — a common issue in older or covered installations — a side mount filter is the right choice. Otherwise, top mount is easier to access for servicing.
In water-restricted areas, a cartridge filter (Astral Hurlcon ZX) is significantly more water-efficient — no backwashing means no water to waste.
Backwash your sand filter when the pressure gauge reads 7–10 PSI above its normal clean operating level — not on a fixed time schedule. Over-backwashing wastes water.
Pool filter sand wears smooth over time, reducing filtration effectiveness. If your water stays cloudy despite correct chemical balance, old sand is often the cause.
Ready to choose your filter?
Browse our full range of Magna-Flo sand filters and Astral Hurlcon ZX cartridge filters — all in stock with fast Australia-wide delivery. Not sure which model is right for you? Our team is here to help.
Shop All Pool Filters Ask Our Team