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Harvey Minimax M3

4th Generation – It led the way.

The Minimax M3 saw the Harvey softener become the most advanced and most tested softener in the UK.

When it was first released, the Minimax M3 led the way in water softening technology, and really ramped up the stakes in reliability, performance and efficiency.

While the Minimax M3 has since been superseded by the environmentally friendly Minimax Innova, the 4th-Generation Minimax M3 is still currently available.

  • Continuous flow rates of 51 litres per minute, and peak flow of 65 litres.
  • An impressively low amount of water is required on a cleanse – just 17.1 litres of water used per regeneration.
  • Suitable for up to 10 people with 2 bathrooms.
  • Offers both high flow rates and high efficiency.
  • The most comprehensive manufacturer-backed parts guarantee EVER
  • Dimensions: (W)206mm (H)490mm (D)445mm


These are some of the features of the Minimax M3:

Smart-Shuttle Metering

Using breakthrough technology, this water softener includes smart shuttle metering. Designed and manufactured to cater to the intricacies of all British plumbing systems. From tanks in the loft to combination boilers and high flow unvented hot water systems, this water softener does the job, perfectly, every time.

Low-Pressure Injector

An enhancement feature that ensures your water softener performs to its full potential. Whether your home is supplied with water at low pressure, or your family requirements cause fluctuations in pressure, our low-pressure injector ensures maximum reliability.

High Flow Rates

The Minimax M3 is designed for all homes and works with all types of plumbing systems. With a continuous flow rate of 51 litres per minute (with minimal pressure loss) and peak flow rates of 65 litres a minute, this is the water softener for you and your home.

Stress Tested

Built for maximum life. While the Minimax M2 was tested at 10-bar pressure for 100,000 cycles, (above the UK standard), the Minimax M3 goes even further. Over 1 million cycles are tested at the higher pressure of 15 bar for total reliability – this massively exceeds the UK standard and represents decades of reliable service.

The salt bay has a red line. If you see the line, it means you can easily get another block of salt in and still get the lid on.