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ScaleSoft® Triple Whole House Hard Water & Chlorine Reduction Filter System| 20" x 4.5" High Flow | WaterMark (GT1-108-SS)
- WaterMark Certified Triple High Flow Filter System, 20" x 4.5"
- Sediment, Carbon and ScaleSoft® Scale Control in One Unit
- Now Supplied with ScaleSoft® SS-20B, Replaces One Stop Plus GT4-86-OSP
- No Salt, No Power, No Drain, No Regeneration
- 16 L/min Service Flow, 60 L/min Maximum Flow*
- Treats Hardness up to 1,400 mg/L
- Retains Calcium and Magnesium
- Upgrade the Carbon Stage to GT4-19LRCP5 for Heavy Metal Reduction
- WaterMark Certified, Certificate No. 23247 to AS 3497:2021
Triple Whole House Hard Water & Chlorine Reduction Filter System | 20" x 4.5"
A three-stage whole house system that treats your water where it enters the property. It reduces dirt and sediment, reduces chlorine, taste and odour, and controls the hard mineral scale that builds up in your plumbing, your appliances and your hot water system.
The scale-control stage is a ScaleSoft® SS-20B cartridge. No salt to buy, nothing to plug in, no drain to connect, and no regeneration cycle to run.
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.
| Housing | Cartridge | Part code |
|---|---|---|
| Stage 1 | Sediment, 5 micron polyspun | GT2-28K |
| Stage 2 | Carbon, 5 micron coconut carbon block | GT4-19CTO |
| Stage 3 | ScaleSoft®, salt-free scale control | SS-20B |
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 | ScaleSoft® | |
|---|---|---|
| Scale control principle | Conditions hardness into stable crystals | Conditions hardness into stable crystals |
| Rated flow, 20" x 4.5" | 15 L/min | 16 L/min |
| pH range | 6.5 to 8.5 | 6.5 to 9.5 |
| Hardness, max | 1,300 mg/L | 1,400 mg/L |
| Cartridge life | Over 12 months | Up to 2 years |
| Position in the system | Middle housing, with a filter after it | Final housing, with the carbon block ahead of it |
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
| ScaleSoft® | Salt-based softener | |
|---|---|---|
| Salt to buy and refill | None | Regular top-ups |
| Sodium added to your water | None | Yes |
| Calcium and magnesium | Stay in your water | Removed |
| Power connection | Not needed | Required |
| Drain connection | Not needed | Required |
| Water sent to backwash | None | Yes, on every regeneration |
| Ongoing upkeep | A cartridge change, about every two years | Salt, servicing and regeneration |
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.
System Specifications
| Model | GT1-108-SS |
| Configuration | Triple stage, 3x 20" x 4.5" high flow housings |
| Cartridge size | 20" x 4.5" |
| Dimensions | Height 70 cm, width 62 cm, depth 20 cm |
| Ports | 1" Female BSP (Stainless Steel) |
| Maximum pressure | 500 kPa* |
| Recommended pressure | 350 kPa to 500 kPa |
| Operating temperature | 0.5 °C to 37.8 °C |
| Maximum flow | 60 L/min |
| Service flow | 16 L/min** |
| Certification | WaterMark Certificate No. 23247, AS 3497:2021 |
Scale Control Cartridge (SS-20B)
| Model | ScaleSoft® SS-20B |
| Rated flow | 16 L/min |
| Peak flow** | 21 L/min |
| Cartridge life | Up to 2 years*** |
| Media | German-made scale-control media |
| Replaces | One Stop Plus GT4-86-OSP |
| Position | Final housing, with the carbon block ahead of it |
| Recommended metal reduction pairing | GT4-19LRCP5 (0.5 micron LRC coconut carbon block) in the carbon housing |
Operating Parameters
| Temperature, cartridge | 0 to 40 °C |
| pH range | 6.5 to 9.5 |
| Hardness (carbonate) | 1,400 mg/L |
| Iron, max | 0.3 mg/L |
| Manganese, max | 0.05 mg/L |
| Free chlorine, max | 3 mg/L |
| Copper, max | 1.3 mg/L |
| Oil, hydrogen sulfide | Free |
Stage Order
| Housing | Cartridge | Part code |
|---|---|---|
| Stage 1 | Sediment, 5 micron polyspun | GT2-28K |
| Stage 2 | Carbon, 5 micron coconut carbon block | GT4-19CTO |
| Stage 3 | ScaleSoft®, salt-free scale control | SS-20B |
Usage Guidelines
- Use on potable mains or treated water supplies only.
- For rainwater tank supplies, talk to us first. Some water sources need testing or pre-treatment before installation.
- Installation must comply with local plumbing codes, and the system should only be connected to the cold water line.
- Protect the system from freezing and do not expose it to temperatures below the minimum operating temperature.
- Flush the system for 30 seconds after periods of non-use exceeding 48 hours.
- Replace the scale control cartridge every 2 years, or sooner if you experience reduced effect or notice sediment build-up. Sediment and carbon cartridges are replaced on their own schedules.
Installation
Position in the system. ScaleSoft® takes the final housing, with the carbon block ahead of it. The order is sediment, then carbon filter, then ScaleSoft®. This removes chlorine, taste and odour before the water reaches the scale-control media, which helps the cartridge run its full service life.
Pressure. Supply above 500 kPa requires a pressure reduction valve fitted ahead of the system.
Certification. This system is certified to WaterMark Standard AS 3497:2021 under Certificate Number 23247. Installation must be carried out by a qualified plumber or authorised technician to comply with Australian Plumbing Codes.
WARNING. For correct operation of this system it is essential to observe the manufacturer's instructions.
CAUTION. Do not use with water that is microbiologically unsafe or of unknown quality without adequate disinfection before or after the system.
Footnotes
* Exceeding the maximum pressure requires a pressure reduction valve.
** Service flow is the scale control cartridge's rated flow, and is the figure to size the system on. Peak flow can maintain scale protection for several minutes of constant flow, and is not the maximum flow rate of the cartridge. Flow exceeding peak flow may have a reduced scale protection effect. Maximum flow is the housing's hydraulic limit, not a treatment rating.
*** Replace the cartridge every 2 years, or sooner if you experience reduced effect or notice sediment build-up.
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.
Return Policy
Due to the nature of the products we sell, a strict return policy is in place. We work with food grade certified materials that must be un-opened and un-used as to be able to be re-sold.
You may receive a refund or credit of equal amount, less the restocking fee if applicable and any other deductions that are relevant.
- Wrongly purchased items may be returned for a merchandise credit, this applies for but not limited to: Wrong size, wrong system etc.
- 30 Day return Policy: Returns will not be accepted without prior approval or after 30 days of invoice date.
- All returns will incur a 17.5% restocking fee or cost to send the item to you whichever greater. FSA may use discretion to determine the restocking fee.
- Any damages (minor, that can be repaired) will incur a fee which will be deducted from the total refund which will be equal to the cost of the replacement
parts (List Price) and labour charge (if applicable) to repair the system(s). This will be separate to the restocking fee. - Any damage considered to be major and not feasible for repair may be refused and the return request will be void. The customer will be responsible for the return freight or disposal of the damaged unit.
- Return shipping is to be paid by the buyer to the address provided. It is recommended that the customer applies transit warranty to the return freight in case of damage.
- Any damages to the system that were not reported to FSA within 48 business hours of receipted delivery are not covered under our transit warranty.
- Should the item appear faulty or doesn’t work how described, the unit/item must be returned for testing (if requested), the return postage paid by the buyer. If the unit/item is deemed to be faulty, compensation will be provided for the postage cost (Proof of cost required). If the unit/item is deemed to be in working order and as described, the buyer will responsible for return postage.
If you have any questions about our return policy, please contact us before purchase. This will also help to ensure you purchase the correct product that suits your requirements.