$119.95 (ex. GST)
✅ Official Doulton Distributor In NZ
✅ Removes microplastics, lead, mercury, chlorine, harmful bacteria and more.
✅ Strips away bad tastes and odours while keeping essential minerals.
✅ Fully certified under NSF and WRAS.
✅ Stop limescale damage using the built-in Scale Inhibition (SI) media.
✅ Fits Doulton underbench and tap-mounted benchtop systems (including DUO, TRIO, and Kingfisher).
⬤ In Stock
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Satisfaction Guaranteed
We guarantee you will be satisfied with your purchase.
If you have a concern when you receive your order, contact us and we will resolve any issue regarding your purchase.
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Removes harsh chemicals and contaminants
Doulton Biotect Ultra cartridges remove microplastics, heavy metals, pesticides, disinfectants (chlorine), pharmaceutical drugs, bacteria and more. Certified by NSF, tested to NSF 42, 53 and 401 standards and test data is made public. The transparency, the extensive lab tests and the superior filter performance across many contaminants set these filters apart from other brands.
Heavy Metals
Pesticides & Herbicides
Particles
Chemicals
Pharmaceuticals
Bacteria
Description
Doulton Biotect Ultra SI 2505 Under-Sink and Countertop Replacement Filter Cartridge
The Doulton Biotect Ultra SI (2505) is a premium, multi-stage ceramic and activated carbon replacement cartridge engineered specifically to deliver clean, great-tasting water while actively preventing limescale build-up. Unlike standard filters that make unverified claims, Doulton products are backed by rigorous testing and WRAS certification. This filter supports your body’s natural detoxification, improves mental clarity, and promotes healthy hydration for a fraction of the cost of bottled water.
If you aren’t using a high-quality water filter, your body becomes the filter.
Why Choose the Doulton Biotect Ultra SI?
Proven Limescale Prevention: Features built-in scale-inhibition media (SI) that protects your coffee machines, kettles, and tapware from stubborn mineral scale build-up.
Comprehensive Contaminant Removal: Effectively filters out microplastics, heavy metals (like lead, cadmium, and mercury), chlorine, agricultural chemicals, harmful bacteria (E. coli) and Giardia cysts.
Retains Essential Minerals: While it targets dangerous contaminants and manages hard water scale, it leaves healthy, naturally occurring minerals intact.
Eco-Friendly & Cost-Effective: Delivers clean water for just a few cents per litre. Choosing this filter saves money on bottled water and eliminates single-use plastic waste from local landfills.
Use Cases and Product Applications
Hard Water Regions: Ideal for households in New Zealand and Australia dealing with high mineral content and limescale deposits on kitchen appliances.
Daily Family Hydration & Cooking: Enhances the natural flavor of coffee, tea, and home-cooked meals by removing unpleasant chemical tastes and odours.
System Compatibility: Designed specifically as a direct replacement cartridge for Doulton benchtop (countertop) and underbench (under-sink) filtration systems, including the Kingfisher, HIP, DUO, and TRIO ranges.
Technical Specifications
| Attribute | Specification |
| Brand | Doulton |
| Model / Part Number | Biotect Ultra SI (2505) |
| Cartridge Height | 254 mm (10 inches) |
| Cartridge Width / Depth | 49 mm |
| Thread Connection | M12 Mount |
| Core Materials | Natural Ceramic Exterior & Proprietary Activated Carbon Block Core |
| Filter Lifespan | 6 Months (or up to 2,300 Litres, depending on source water quality) |
| Certification | NSF, WRAS Certified (No. 2204074) |
What’s in the box
1x Doulton Biotect Ultra SI Ceramic Filter Element.
Frequently Asked Questions
How often do I need to replace this water filter?
We recommend replacing the cartridge every 6 months. If you notice a reduction in water pressure or a change in taste before this time, it indicates the filter has successfully trapped a high volume of sediment and should be replaced or cleaned according to the instruction manual.
Will this cartridge fit non-Doulton water systems?
The Biotect Ultra SI features an industry-standard M12 thread. It fits all genuine Doulton under-sink and tap-mounted countertop systems. For other brands, please verify the thread size before purchasing.
Shipping and Delivery Information
All orders are processed and dispatched directly from our warehouse.
New Zealand Shipping
Free Shipping: On all orders over $399 (excluding GST).
Flat Rate Shipping: $9.95 (excluding GST) for orders under $399.
Carrier: Tracked NZ Post delivery (1 to 8 working days).
Australia Shipping
Free Shipping: On all orders over NZ$399.
Flat Rate Shipping: NZ$39.95 for orders under NZ$399.
Carrier: Tracked international delivery (5 to 10 working days).
Buy Risk-Free
Your purchase is backed by our 30-day money-back guarantee as outlined in our terms and conditions.
Reviews (10)
10 reviews for Doulton Biotect Ultra SI 10″ Replacement Filter Cartridge (Model 2505)
Only logged in customers who have purchased this product may leave a review.
Why This Is A Superior Product
| Doulton | Other Brands | |
|---|---|---|
| A brand that is trusted worldwide | ✓ | ✗ |
| Certified by NSF | ✓ | ✗ |
| Removes a wide range of contaminants | ✓ | ✗ |
| Tested to NSF 42, 53, 401 standards | ✓ | ✗ |
| Lab reports available to back up claims | ✓ | ✗ |
Our Promise: 100% Satisfaction Guaranteed
We stand behind the quality of our products. When you invest in your health with us, your purchase is completely risk-free. If you have any questions or concerns when your order arrives, contact our local New Zealand support team and we will make it right.
Jasper –
Have been a faithful Doulton customer for years now, and this is pretty much my go-to filter for my under the counter system hooked up to the 3-way tap. Water tastes great, so I trust it does its job and keeps all the bad stuff out.