ScaleSoft® Triple Whole House Hard Water & Chlorine Reduction Filter System| 20″ x 4.5″ High Flow | WaterMark (GT1-108-SS)

Now supplied with ScaleSoft®

This system was previously supplied with the One Stop Plus cartridge. ScaleSoft® supersedes it across the whole range. It works on the same salt-free scale-control principle, fits the same housing, and carries more rated flow.

If you have this system already, SS-20B is the replacement for your GT4-86-OSP cartridge. It is a direct swap. Same housing, same fittings, no plumbing changes.

What is the issue with hard water?

• It builds up inside kettles, dishwashers and coffee machines, and shortens their working life.
• It coats the elements in hot water systems and the inside of your pipework.
• It leaves spotting and film on taps, shower screens and glassware.

The level of hardness in your water depends on where your supply comes from. Many parts of Australia are known for soils with high mineral content, and hardness varies widely between regions.

How the scale-control stage works

Step 1. Water enters the cartridge. Hard water carries scale-forming calcium and magnesium, which are attracted to the ScaleSoft® media.

Step 2. The scale-control media converts those minerals into microscopic, stable crystals. Once the crystals become too large, they detach from the media.

Step 3. The crystals stay suspended and flow through with the water, instead of bonding to your pipes and elements.

Worth knowing. ScaleSoft® conditions hardness rather than removing it. It is a scale-control cartridge, not an ion exchange softener, which is exactly why it needs no salt, no power and no drain.

Where each cartridge sits

One Stop Plus was specified in the middle housing, with a filter after it. ScaleSoft® can take the final stage instead, which puts the carbon block ahead of it. Chlorine, taste and odour are taken out before the water reaches the scale-control media. That is easier on the cartridge and helps it run its full service life.

This is the order the system is supplied in. If you are replacing cartridges in an older system that was set up the other way around, move the carbon block ahead of the scale-control cartridge at the same time.

What you gain over the One Stop Plus system

One Stop Plus figures are taken from the manufacturer’s published datasheet and from our own product listing. ScaleSoft® figures are taken from its published specification.

Why people choose this system

• Three stages, one install: sediment, carbon and scale control in a single pre-assembled unit.
• No salt or regeneration: nothing to refill and no regeneration cycle to run.
• No power or drain required: no electrical connection and no drain line, so it fits where a softener will not.
• Retains calcium and magnesium: the naturally occurring calcium and magnesium stay in your water.
• No intended change to pH or TDS: your water’s pH and dissolved solids are not intentionally altered.
• Protects plumbing and appliances: helps protect pipes, hot water systems and appliances from scale build-up.
• WaterMark certified: Certificate No. 23247, so it can be installed by a licensed plumber.

This system next to a salt-based softener

Important notes

ScaleSoft® conditions water to prevent and reduce scale, but it does not remove calcium or magnesium from the water. You may still see these minerals on surfaces where water is allowed to dry. Those deposits are less adherent and easier to clean than untreated water. On glass shower screens, squeegee or dry the glass after use to prevent spotting.

ScaleSoft® reduces the formation of hard mineral scale. It is not a disinfection or purification device, and it is not an ion exchange water softener. Suitable for mains and treated water.

For the full technical specification and installation information, see the Specs/Performance tab.

Reducing heavy metals

One Stop Plus carried a blended media that also offered some reduction of dissolved metals. ScaleSoft® is purpose-built for scale control, so where metal reduction is part of the specification, it is handled by the carbon stage instead. Choose cartridge set 2 below, which fits an LRC 0.5 micron coconut carbon block in the carbon housing. It is the dedicated route, and it matches the housing size one for one.

For this 20″ x 4.5″ system, the pairing is GT4-19LRCP5.

System contains

• 3x 20″ x 4.5″ high flow housings, pre-assembled with bracket affixed
• 1x Sediment cartridge, 5 micron polyspun (stage 1)
• 1x Carbon cartridge, 5 micron coconut carbon block (stage 2)
• 1x ScaleSoft® cartridge, salt-free scale control (stage 3)
• Opening handle to suit 4.5″ housings (GT17-2S)
• 3x 1/4″ plugs and seals to suit the 20″ housing pressure gauge port

Choosing your cartridge set

There are several options for the sediment and carbon stages, and they suit different supplies. Below are the most common configurations. These are general recommendations only and may not suit every situation. If you are unsure, contact us before ordering so you get the right cartridges.

Set 1. Standard, chlorinated mains water

The set that suits the largest number of installations. It covers dirt and sediment, chlorine and other chemicals, and hard water scale.

• Stage 1, sediment. 5 micron polyspun sediment filter (GT2-28K)
• Stage 2, carbon. 5 micron coconut carbon block (GT4-19CTO)
• Stage 3, scale control. ScaleSoft® SS-20B

Set 2. Premium, chlorinated mains water plus heavy metal reduction

Swaps the carbon block for a lead and heavy metal reduction block. This is the set to choose where metal reduction is part of the specification.

• Stage 1, sediment. 5 micron polyspun sediment filter (GT2-28K)
• Stage 2, carbon. 0.5 micron lead reduction coconut carbon block (GT4-19LRCP5), or the 5 micron version (GT4-19LRC05)
• Stage 3, scale control. ScaleSoft® SS-20B

The 0.5 micron block is best suited to supplies running between 350 and 500 kPa. If your pressure is average or lower, talk to us before choosing it.

Set 3. Premium, chlorinated mains water plus chloramine reduction

For mains supplies disinfected with chloramine rather than chlorine. Chloramine is used across much of metropolitan Australia, including Sydney, Brisbane and Melbourne, and widely in WA and SA. Your local water provider or council can confirm which is used in your area.

• Stage 1, sediment. 5 micron polyspun sediment filter (GT2-28K)
• Stage 2, carbon. 0.5 micron chloramine reduction catalytic coconut carbon block (GT4-19CRC)
• Stage 3, scale control. ScaleSoft® SS-20B

The 0.5 micron block is best suited to supplies running between 350 and 500 kPa. If your pressure is average or lower, talk to us before choosing it.

Other water supplies

Water from a private or untreated supply can carry a wide range of contaminants, and we cannot recommend a cartridge set for one without a current water analysis. Contact us and we will point you to the analysis service.

Optional extras

Pressure gauges (GT16-3S). Gauges let you see the pressure before and after the filters, which is the easiest way to tell when a cartridge is loading up and due for a change. They also make troubleshooting a restriction or a leak much quicker.

Enclosures. The system is supplied on a powder coated steel backing plate (GT1-9TWM). A stainless steel version (GT1-9TWMS) is available and is the better choice for outdoor installations.

If you do not know your supply pressure, our water pressure test kit will confirm the install conditions are inside this system’s specification before you order.

WaterMark certified

This water filter system is certified to WaterMark Standard AS 3497 under Certificate Number 23247. WaterMark certification is a mandatory requirement under Australian law for water filter systems to be installed by licensed plumbers. Products bearing this certification meet rigorous Australian plumbing and water safety standards, ensuring compliance and reliability. Our WaterMark-certified filter systems are hand-assembled in Australia and undergo random batch testing to maintain the highest quality and workmanship, giving you confidence in the safety and performance of your water filtration products.

ScaleSoft® is a product brand of High Performance Filtration.