CTO Max Twin Under Sink Water Filter with Fluoride Removal for Hard Water
$539.00 inc. GST
You want to feel confident about the water you and your family drink every day. But in hard water areas like WA, NT, SA and parts of QLD, it’s not just the contaminants that are a concern, it’s also the limescale that builds up in your kettle, clogs your filters, and affects your appliances over time.
- UK-made ceramic filters remove fluoride, chlorine, chloramine, PFAS, microplastics, heavy metals, and organic contaminants.
- US-made Inline phosphate cartridge made by Omnipure helps reduce mineral scale build-up
- Certified to NSF/ANSI 53 & 42 standards for effective contaminant removal you can trust.
- Hand-built in Sydney and backed by a 5-year housing warranty. Fully compliant with Watermark AS/NZS 3497:1998.
- DIY-friendly setup — install this undersink water filter system yourself or get a plumber to do it for you. It’s simple either way.
Description
Certified Under Sink Water Filtration
This system meets the WaterMark specification AS/NZS 3497:1998 Amdt 1 2001 Drinking water treatment unit – Plumbing requirements.
Certificate Number 23124.
- Aluminium
- Barium
- Cadmium
- Chloramine
- Chlorine
- Chromium
- Copper
- Cryptosporidium & Giardia
- Cysts
- e. Coli Bacteria
- Fluoride
- Heavy Metals
- Hydrocarbons
- Iron
- Lead
- Manganese
- Mercury
- Microplastic
- Nitrate
- PCB’S
- PFAS
- Potassium
- Radium
- Sediment, Dirt & Rust
- Selenium
- Sodium
- Aluminium
- Barium
- Cadmium
- Chloramine
- Chlorine
- Chromium
- Copper
- Cryptosporidium & Giardia
- Cysts
- e. Coli Bacteria
- Fluoride
- Heavy Metals
- Hydrocarbons
- Iron
- Lead
- Manganese
- Mercury
- Microplastic
- Nitrate
- PCB’S
- PFAS
- Potassium
- Radium
- Sediment, Dirt & Rust
- Selenium
- Sodium


Everything You Want to Know (At a Glance)
Quick Answers
How often do I need to change the cartridges and how much do they cost?
CTO Max Cartridges: every 6–12 months, $219 discounted twin set (single cartridge $120).
Omnipure K5485-BB Phosphate Inline Cartridge: every 6 months or 5,700 litres: $79
Can I install this under sink filter myself?
Yes, you can install this undersink water filter yourself if you have basic plumbing skills. It’s WaterMark approved, meaning it meets Australian plumbing standards. If you prefer, your local licensed plumber can install it for you as well.
What contaminants does it remove?
This under sink water purifier removes over 130 chemicals incl. chlorine, chloramine, fluoride, herbicides & pesticides, bacteria, virus, PFAS, microplastics, heavy metals.
How do I replace the cartridges?
Simply twist open the housing, remove the old cartridge, insert the new one, and twist the housing closed. No special tools required – it’s quick and easy!
What happens if it doesn’t work for me?
We’re here to guide you through every step, and while issues are rare, if something truly doesn’t work out, we’ll always honour our return policy on unused systems.
Specifications
- Filter output up to 10,000 litres, for optimal performance we recommend replacing the filters every 6-12 months
- 0.9 Micron absolute
- Dimensions: 23(W) x 45 (H) x 13(D)
- Cartridge sizes: 9″ x 2.5″
- Maximum flow rate: 2.5 litres per minute
- Warranty: 5 years (housing)
Replacement Filter Cartridges

The system requires 2 of these cartridges to be replaced every 6-12 months for optimal performance.
You want clean, safe water for your family—and the Coldstream CTO Max helps you get there. This all-in-one cartridge removes over 130 contaminants, including Fluoride, Chlorine, Chloramine, PFAS, heavy metals, bacteria, and viruses. With its advanced dual-layer design, it fits standard benchtop water filters & undersink water filters and delivers peace of mind with every glass. Certified to NSF standards and built in the UK, it’s one of the best PFAS water filters available.
Say goodbye to hard water hassles with the Omnipure K5485-BB phosphate inline cartridge. Designed to reduce limescale and mineral buildup, this 5-micron filter protects your water filter cartridges extends the life of your under sink water filter system. Perfect for hard water areas, it fits compactly in line before your filtration cartridge, preventing scale damage to your appliances. Made in the USA by trusted Omnipure, the K5485 offers reliable pre-treatment with easy installation. Designed to last up to 6 months or 5,700 litres, it keeps your water flowing smoothly and your system protected.
Hassle-Free Installation
Installation of your twin undersink water filter system is straightforward with the included guide and complete package of parts. All necessary fittings, tubing, and adapters are provided for a seamless setup.
We want to ensure your installation experience is easy and stress-free. Please reach out to our support team with any questions!
Installation Diagram

Filter Componants

- A – CTO Max Cartridge
- B – CTO Max Cartridge
- 1 – Housing Sump
- 2 – Housing Cap
- 3 – Stainless Steel Bracket
- 4 – Pressure Limiting Valve (PLV)
- 5 – John Guest Elbow (with red clips)
- 6 – Brass Nipple
3 Simple Steps to Safer Water — with Free Shipping Australia-Wide:

Choose Your Filter – Order the CTO Max Twin for Hard Water and join our Water Tribe.

We Build & Send – Each unit is assembled in Sydney with care and shipped with tracking.

Install & Enjoy – Fit it yourself or have a plumber install it. Enjoy clean, balanced, great-tasting water from your tap.
How We Got Here And Why It Matters
When we first looked into water filters, we were completely overwhelmed. So many options, so much jargon. That journey led us to start Living Whole, one filter at a time — from our first water distiller to benchtop water filters and then reverse osmosis. Everything in our shop is something we’ve personally researched and trust. Now, after almost a decade in business and over 40 years of combined experience, we’ve helped thousands of families find the right filter for their home. Here is what they say:
Clean Water Shouldn’t Be Complicated — Just Clear, Safe, and Ready
At Living Whole, we understand that you simply want to feel at ease about the water you and your family use every day.
The problem is, tap water doesn’t just carry things like chlorine, heavy metals, and PFAS — in many parts of Australia, it’s also hard, leaving scale in your kettle, clogging your appliances, and shortening the life of your filters. That can leave you feeling frustrated and unsure.
We believe you shouldn’t have to second-guess something as essential as your water.
Here’s how it works:
- Choose the CTO Max Twin Under Sink Water Filter with Fluoride Removal for Hard Water.
- We assemble everything and send it ready to install.
- Fit it once and enjoy clean, scale-reducing filtration every day.
Order your under sink water purification system today so you can stop worrying about what’s in your water — and start feeling calm, confident, and clear.
What You’re Avoiding
- Limescale in your kettle, water filter, and on your tapware
- Worries about PFAS, chlorine, or fluoride
- Endless research and filter confusion
What You’ll Gain
- Clean, better-tasting water — every time
- Protection against scale build-up
- Confidence in your wellness choices
- A more sustainable, clutter-free kitchen
Choose Your Under Sink Water Filter Tap
All our under sink water filter taps include a base plate and connection fittings.
* Please Note: the width (W) refers to the dimension from the centre line of the tap body to the centre of the spout.

Retro with High Loop
Standard Retro faucet in a high loop design and long reach.
125mm W x 235mm H

Metro with High Loop
Standard Metro faucet in a high loop design.
160mm W x 250mm H

Antique
Standard Antique faucet in a high loop design.
125mm W x 235mm H

Euro with Long Reach
Standard Euro faucet in a long reach design.
150mm W x 230mm H

Side Lever High Loop 3-Way Mixer Chrome
The Side Lever High Loop 3-Way Mixer Tap in Chrome features a sleek high-loop design, providing hot, cold, and filtered water from a single tap.
203mm W x 365mm H

Side Lever Long Reach 3-Way Mixer Chrome
The Side Lever Long Reach Mixer Tap features a simple yet elegant design, providing hot, cold, and filtered water from a single tap.
195mm W x 325mm H

3-Way Mixer Tap Standard Chrome
The 3-Way Mixer Tap Standard Chrome comes in a sleek long-reach design, providing hot, cold, and filtered water from a single tap.
245mm W x 180mm H

Stainless Steel 3 Way High Loop Matte Black Mixer Tap
The Stainless Steel 3 Way Mixer Tap features a high loop design in a matte black finish, providing hot, cold and filtered water from a single tap.
225mm W x 400mm H
Data Sheets & Test Reports
Additional information
Weight | 2.5 kg |
---|---|
Dimensions | 36 × 36 × 15 cm |
Alkaliser | AlkaHydrate (made in Asia), Omnipure (Made in USA) |
1 review for CTO Max Twin Under Sink Water Filter with Fluoride Removal for Hard Water
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Geoff –
Good product, feels well made and robust. The real benefit of this filter is the filter cartridges themselves which are certified to the US NSF standard, the results of the testing can be found online so you can be confident exactly what the filters are removing. Took about a week to receive the filter, it arrived already assembled with just the ministop valve, tap and connecting water tubes needing to be installed under the sink. All quite straight forward, but surprising no instructions were included in the box (just download it from the website).
Be aware that as this uses two ceramic filters, there will be a little reduction in water pressure compared to other non ceramic water filters. Water tastes good.
I did raise one question to which I received a prompt reply.
Living Whole –
Hi Geoff! Thank you so much for the detailed review! We’re happy to hear you’re satisfied with the product and the quality of our certified filters