340mm x 126mm RDC 25 - Replacement Cartridge Filter

Premium Quality. Trusted Brands. No Gimmicks. 

Heater & Spa Parts only supplies premium-grade filter cartridges — no cheap Chinese generics, no rebranded knock-offs, and no gimmicks. Our filters are trusted by major spa and pool brands including Astralpool, Balboa, Davey, Halo Spas, Hurlcon, Oasis Spas, Sapphire Spas, Spa World, Vortex®, SpaNet, Waterco, Zodiac and more.

These aren’t your cheap filters sold on eBay, Wish, Temu, or Amazon. They are the same filters used by top manufacturers. Because we buy in container-load volumes, we’re able to offer the same high-end filters at a much better price — and pass those savings on to you.

NSF® Certified for Safety and Performance

All our filters are made from NSF® certified materials — meeting international standards for safety, strength, and water filtration performance. Brands like Darlly®, Magnum®, Pleatco®, and Reemay® are globally recognised for quality and reliability. If leading spa and pool equipment manufacturers rely on them, so can you.

Why We Use Darlly® and Magnum® Filters

Unless otherwise specified, we supply filters from Darlly® and Magnum®, made with advanced media from Reemay® or equivalent. These filters offer:

• Stronger, continuous fibres for minimal shedding
• Greater durability compared to cheap alternatives
• Longer life and fewer replacements
• Cleaner, healthier water

Low-quality filters often shed fibres that clog or damage equipment. Ours are engineered to avoid that — keeping your spa or pool clean and efficient.

Filter Cleaning Guide

Proper maintenance extends the life of your cartridge and keeps water quality high. Clean your filter when:

• Spas: Water flow or jet pressure drops
• Pools: Filter pressure is ~35kPa higher than normal

How to Clean Your Filter

1. Remove the cartridge per manufacturer instructions
2. Soak it in a cleaning solution (e.g., Zodiac Filter Soak or Filter Klenz)
3. Rinse thoroughly with a garden hose — pleat cleaning nozzles help
4. Reinstall the filter carefully

Maximise Filter Life

• Maintain balanced water chemistry
• Clean regularly based on system usage
• Do not scrub with hard brushes or use high-pressure hoses
• Avoid using flocculants and overusing clarifiers
• Rotate multiple cartridges to extend lifespan

When to Replace Your Filter

We recommend replacing your filter every 12 to 24 months depending on usage and conditions. Keeping a spare on hand allows for uninterrupted filtration and longer lifespan through rotation.

Warranty Information

All standard filters are covered by a 12-month replacement warranty (excluding disposable/inflatable types). This covers defects in materials or workmanship, not damage from improper use or poor water chemistry. See examples and warranty terms here.

In Summary: Why Choose Our Filters?

• NSF® certified materials for proven safety and performance
• Used by major brands – AstralPool, Balboa, Davey, Halo Spas, Hurlcon, Oasis Spas, Sapphire Spas, Spa World, SpaNet, Waterco, Zodiac
• Made by Darlly®, Magnum®, Pleatco® – not unknown generics
• No gimmicks – just reliable, proven filtration
• Engineered for Australian conditions – reliable year-round

Your spa or pool deserves more than a “just good enough” filter. Choose proven quality, backed by trusted names and expert knowledge.

Want to Know More? Read More...

Measuring a cartridge filter element when you dont have the exact model is the best way to identify it. There are a few important measurements, and they need to be as accurate as possible. 

Total Length: Length of the filter, excluding the handle. You can generally also exclude the spigot or thread.

 

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Diameter: This is the width of the filter.

 

 

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Spigot Diameter: You may have a male threaded, or non-threaded spigot to locate the filter.
Hole Diameter: If you have a hole, rather than a spigot, measure the diameter of the hole.