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Compact Undersink Reverse Osmosis Water Filter System | pH Neutralising (GT1-70Compact)

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Quick Overview
  • Compact Under Sink RO System with Low Pressure Membrane
  • Perfect for Filtering Fluoride and Chlorine on Mains Water
  • Can be used on Rain/Tank/Bore* Water Provided Sufficient Disinfection of the Source Water
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Compact Undersink Reverse Osmosis Water Filter System | pH Neutralising (GT1-70Compact)

The Compact Undersink RO system has been specifically designed to suit the needs of customers with under sink space restrictions or issues with low water pressure. This set-up features a compact filter body with a carbon pre-filter (to remove chemicals, tastes & odours), a low-pressure RO membrane (to reduce heavy metals, fluorides and salts by up to 98%), and a Calcite (Calcium-based) & Coconut Carbon pH Neutralising Post-Filter (to provide sweet-tasting drinking water with an ideal pH of 7-8).

Important Notes Before Purchasing:
  • Please note that if this system is used after a water pump (i.e. a non-mains-water source), if there is no water pump accumulator (bladder) on the pump, this will cause the pump to cycle in and out continuously whilst the system re-fills. This will stop once the RO Water Storage Tank is full. 


pH Neutral Water in the Compact/Low Pressure System | The 3 Stages of Filtration

Stage 1: 5 Micron Inline Coconut Carbon Block (Replace Every 6 Months)

The Purefer 5 Micron Inline Coconut Carbon block pre-filter prevents sediment from physically clogging your RO membrane, all the while removing Chlorine, Chloramines, Chemicals (Pesticides, Herbicides, THMs, VOCs etc), Tastes and Odours. 

Stage 2: 0.0001 Micron 50 GPD Reverse Osmosis Membrane (GT13-3LP) (Replace every 1-4 years depending on water quality)

Unlike a standard membrane, the 50GPD Low-Pressure membrane works in a range of pressure environments. With pressures as low as 25psi the system will produce approximately 2 litres of drinking water per hour, whereas in standard mains pressure scenarios (70psi) the membrane will produce around 7-8 litres per hour.

Stage 3: Dual Finishing Cartridge: Activated Coconut Carbon/Calcium Alkalising Post-Filter (GT6-18LS) - (Replace Every 12 Months)

The last stage features a high grade of activated coconut carbon to impart a naturally sweet taste, which then passes through calcite (CaCO³) alkalising media to raise and buffer the final pH to between 7-8, without causing hardness. Note that upon installation, a new Calcium Alkalising cartridge may register an initial pH higher than 8, but it will quickly balance out.

Stage 4: Inline Magnetic Water Conditioner (Never Needs Replacing)

The effects of magnetization on the physicochemical properties of water have been well documented in scientific literature for several decades, with findings ranging from the application of magnets to reduce the growth of limescale in pipes, through to the documentation of magnetically treated water being used to improve the quality and quantity of fruit yield in capsicum plants and increasing the level of oxygen in water to improve hatch rate of fish eggs.


Faucet Tap Options

All of our under-sink RO systems come with a dedicated drinking water faucet tap as standard – which means you will need to drill a hole into your sink or benchtop to install it. Alternatively, you can swap out your current faucet for a 3-way mixer tap, which includes all 3 lines in the one faucet (Hot, Cold & Filtered) – this is a great option for those who don’t want to drill (i.e. if you have a stone benchtop), and it also looks nice and minimalistic. If you would like to explore our range of faucets and mixer taps in better detail, please click the below:


RO Water Storage Tank Options

Because Reverse Osmosis membranes filter down to such a fine micron rating (0.0001 of a micron), they produce water at a very slow rate (on average 8 litres PER HOUR). This is why all plumbed-in RO systems come standard with a dedicated drinking water tap, and a water storage tank. Your water usage requirements and under-sink space can help determine which sized tank to choose from. Consider that the average person should drink 2L of water per day, and that the system will automatically re-fill at a rate of 8 litres per hour. Choose from a 6L, 8L or 12L tank - the tank dimensions can be seen in the image below:


Please refer to the "Specs/Performance" Tab for system dimensions. 

Watermark Certification

This RO system is certified to WaterMark Standards AS/NZS 3497 under Certificate Number 23247. WaterMark certification is the level of certification required by law for a licensed plumber in Australia to install a water filtration system. All products used under this certification will give you peace of mind knowing that your water filter complies with Australian plumbing codes. Our WaterMark Certified filter systems are hand-assembled here in Australia and are randomly batch-tested to ensure top quality and workmanship for your water filtration products. WaterMark Certification not only covers materials for structural integrity under pressure, but it also requires that all components (including filters) meet National Sanitation Foundation (NSF/ANSI) 42 Standards or higher. Do not trust products that do not have WaterMark Certification - they can be hazardous to your health and may result in denied insurance claims due to Australia's Plumbing & Drainage Laws. 

INSTALLATION - Please note this system is WaterMark Certified to Australian plumbing standards (AS/NZS 3497), and will need to be installed by a licensed plumber. Simply order online with free shipping to your home, and once it arrives any local licensed plumber will be able to do the installation (the system also comes with instructions)!



Our Thoughts On Fluoride

Whether or not you agree or disagree with the fluoridation of Australian Tap Water, most municipalities in Australia have adopted the practice of adding fluoride due to its dental health benefits. Fluoride has been proven to help remineralise and strengthen the tooth enamel to prevent cavities and tooth decay with incredible effectiveness, hence why it is the most common ingredient in mainstream toothpastes! However, too much fluoride (or exposure to fluoride in childrens' developing teeth) can cause dental fluorosis - a condition characterised by unsightly discolorations and small white spots visible on the surface of the tooth. Whilst rare, fluorosis can actually damage the surface of undeveloped teeth, weakening them in the long run.

Dental Fluorosis of the teeth.

Of course, as with any miracle of modern medicine, it is true that "the dose makes the poison". At high doses, Fluoride is a proven neurotoxin - as shown in countless credible studies - and this is why all fluoridated toothpastes must list the fluoride content and warn you not to swallow it! However, in spite of its clear dental health benefits, a simple Google Scholar search of academic research articles on "chronic exposure to fluoride" will help educate you on what is currently known about the long-term consequences of ingesting fluoride. Fluoride is good for your teeth, but do you really want to be consuming it?

Reverse Osmosis Water Filtration is the safest and most effective solution to remove fluoride from your drinking water, as fluoride is a Mineral Salt. Mineral salts will pass straight through standard sediment and carbon filtration, however, using a 0.0001 Micron reverse osmosis membrane offers a 98% reduction in fluoride (in addition to heavy metals and salts). 

(Fun Fact: Fluoride isn't the only compound capable of remineralising your teeth! For example, in Japan, one of the most popular toothpaste brands (Apagard Toothpaste by Sangi Co.) was originally developed for NASA and used by astronauts in space! This toothpaste contains a calcium phosphate mineral compound called Nanohydroxyapatite (Nano-HA or nHAP) - a totally natural, bio-compatible substance that mimics the natural calcium hydroxyapatite structure of teeth and bone, penetrating deeper than fluoride to strengthen (and whiten) the tooth more effectively and without the negative effects of fluoride!)


Re-Mineralising & Alkalising - What Does It Mean?

Reverse Osmosis Water Filtration has long divided public opinion with common myths such as "RO water is too pure", "RO leaches minerals from your bones" and "RO removes beneficial minerals". However, Reverse Osmosis technology has been risk-assessed by the WHO and safely used for many decades to supply water to the public in places where fresh water is scarce. For example, many people already know that RO technology is used widely in the Middle East and in sub-marines to turn salty ocean water into fresh drinking water... but did you know Australia also has seven desalination plants that supply water to Sydney in NSW, the Gold Coast in Queensland, Adelaide in South Australia, Dalyson in Victoria, and in Perth, Cape Preston, and Binningup WA? You might already be drinking RO-filtered tap water in your home and not even know it!

The misconception that water can be “too pure” has to do with the pH chemistry of water. Water that is “too pure” is simply water that contains little to no mineral content. The way Reverse Osmosis works is by filtering down to such a fine micron rating (0.0001) that almost all dissolved metals, minerals, and salts are removed - leaving you with incredibly pure water. However, the absence of minerals leaves the water with an acidic pH of around 5-6. Now, it's common knowledge that acidic drinks (such as soft drinks and alcohol) are proven to corrode tooth enamel (perhaps that's where the myth of "RO leaches minerals from your bones" originates), and hence why we don't recommend you drink acidic RO-filtered water straight out of the membrane! Instead, the solution is to use a "post-filter" after the membrane to add the minerals back in and bring the pH and alkalinity back to a non-corrosive state! 

Now, this is where we will myth-bust the idea that "RO removes beneficial minerals". When we consider nutrition, minerals come in two main forms - inorganic minerals and organic mineral compounds. The inorganic form is basically a mineral electrolyte in its raw state (i.e. directly from the earth), but on its own, inorganic minerals are negligibly bioavailable. Plants turn inorganic minerals into organic mineral compounds via photosynthesis - hence why fruits and vegetables are so nutritious! Animals and humans also have the ability to transform inorganic minerals into bio-available organic mineral compounds through the digestive process (i.e. chelation in the stomach). It is commonly known that vitamin C improves the absorption of iron, which is a great example of how chelation works! To give you another perspective, spinach is considered to be one of the most magnesium-rich foods (79mg of magnesium per 100g). When we consider that (as an example) Gold Coast Tap Water contains on average, a mere 4.2mg of magnesium per litre of water - you'd have to drink 18 litres of water to get the same amount of magnesium! 

As with anything we consume, digestion is never 100% efficient! So, the reality is that YES - even though RO removes minerals, and even though the post-filter remineralises the water, and even though the human body has the ability to convert inorganic minerals into organic mineral compounds - you still get more mineral nutrition from eating wholesome pre-digested readily bio-available organic minerals in meats, fruits, and vegetables than you do from drinking water!

How often should you change reverse osmosis water filters?
Filter Replacements & Maintenance Schedule

To maintain the optimum level of filtration year-round, and to ensure you get the maximum life out of your RO membrane (the engine room of this system), we strongly recommend a consistent filter maintenance schedule. 

  • Pre-Filters

    Every 6 months you will need to change the pre-filters, which help protect and extend the life of the membrane. Some people neglect to keep up with the maintenance of the pre-filters, thinking that the RO membrane will take care of it! However, the RO membrane is the most delicate and expensive filter within any RO system, so it's worth protecting your investment!

    The pre-filters thus serve the dual purpose of blocking sediment particles larger than 5 microns and removing chlorine, which both cause damage to the inside of the RO membrane in different ways:

    • Sediment particles physically damage the fine internals, causing micro-tears that allow contaminants through to the "clean" side of the osmotic membrane, as well as blocking up the membrane which can cause the system to stop producing water and force an excessive amount of water to waste. 

    • Chlorine that has been dissolved in water creates corrosive hypochlorous and hydrochloric acids, which dissolve the delicate RO membrane (via a process called "ring chlorination" which disrupts the hydrogen bonding between the membrane's polymer matrix) and allows contaminants to pass through to the "clean side". Because this process occurs gradually over time, most people don't notice the taste of contamination until they change their membrane! 

  • Reverse Osmosis Membranes*

Reverse Osmosis membranes filter down to an ultra-fine level of filtration - down to 0.0001 of a micron - which is the reason why RO membranes can filter out minerals, salts, and metals (unlike carbon). Because this level of filtration is so fine, RO membranes do eventually clog up over time. How long you will be able to get out of your RO membrane, depends on the consistency of your membrane pre-filter maintenance, along with the starting quality of your water.

Schematic diagram of the pores in a reverse osmosis membrane.

(Adapted from Geise, G.M., 2021, found in https://www.science.org/doi/10.1126/science.abe9741)

    • HARD WATER (water that is full of salts and minerals) takes a bigger toll on RO membranes than water that is SOFT (water with a low Total Dissolved Solids rating).
    • Western Australia, South Australia, the Northern Territory and Queensland tend to have hard water, along with those whose main source of water comes from a bore.

    • Thus, whilst we have specified a recommended maintenance schedule (below), the quality of the water in the area you live, is ultimately what will determine how long you get out of your RO membrane.

    • *If you are on hard water, at the 2-year mark, simply go for the FULL Replacement Pack (which includes an RO Membrane). Note - cases of extremely hard water may get less than 2 years out of an RO membrane. 

Australian Water Hardness Map Guide

  • Post-Filters

These are all filters that go after the RO membrane to buffer the pH back up from an acidic state to an alkaline state, and "perfect" the water for final consumption. Over the course of a year, the diffusion of the alkalising minerals into the water will significantly diminish, whilst the carbon post-filter will eventually exhaust its capacity to adsorb residuals. 

Please see the Recommended Filter Replacement Schedules (per the above) and links to the replacement filters:

HARD WATER - Recommended Filter Replacement Schedule*

MODERATE/SOFT WATER - Recommended Filter Replacement Schedule



Disclaimer: Do not use or drink microbiologically unsafe water or water of unknown quality without adequate disinfection.


FSA’s Recommendation for Rain/Tank/Potable Bore Water*

If you use Rain/Tank Water and Potable Bore Water (*i.e bore water that has been tested to the Australian Drinking Water Guidelines and deemed suitable for drinking purposes per the Guidelines’ aesthetic, health and safety recommendations), please see below our recommended filtration schedule to ensure safe drinking water:

  1. External Sediment + Carbon Pre-Filtration to Prevent Tank Clogging + Improve Initial Taste & Odour
  2. Tank Dose with HydroSil Ultra 7.5% for Protection Against Bacteria & Viruses
  3. Undersink <1 Micron Absolute Filter for Protection against Parasites & (Optional) Coconut Carbon for Improved Final Taste & Odour

Read on for a full explanation of why we recommend this as the minimum standard of filtration for treating Rain/Tank/Potable Bore Water for drinking.

For Protection Against Bacteria/Viruses

Bacteria (such as E.Coli) can colonize in the stagnant water and result in harmful illnesses when consumed. For sanitation against common water-borne bacteria/viruses in rainwater and potable bore water*, we, therefore, recommend dosing your tank with a product such as Hydrosil Ultra 7.5% Water Sanitiser to ensure protection against microbiological contamination/biofouling in your pipework and/or filter system.

HydroSil is a food-grade silver-activated, hydrogen-peroxide based water sanitiser, which acts to oxidise bacteria, yeast, fungi & viruses, without leaving any dangerous residues behind. HydroSil sanitizes and protects your tanks and water storage devices, making rainwater and potable bore water safe and suitable for human consumption. HydroSil is not a chlorine-based chemical like most sterilisers on the market today. It is non-toxic, and safe to use around your home and family.

Dosage Rate: HydroSil should be dosed at a rate of 200mL per 1000L of water. To scale down to tank size, you will require 20mL per 100L.

Buy Hydrosil Ultra 7.5% Here:

For Protection Against Parasites/Protozoa

Ingesting waterborne parasites (Protozoan Cysts) such as Cryptosporidium and Giardia (which flourish in raw water sources such as rain water tanks and bores), are a common cause of gastroenteritis. Whilst Chlorine can inactivate Giardia with a moderate dose and contact time, Chlorine has a negligible effect on Cryptosporidium unless dosed in excess of the acceptable Chlorine limit per the Australian Drinking Water Guidelines (Version 3.6, pp. 200).

For protection against these common cysts, we, therefore, recommend under sink filtration down to at least 1 Micron (Absolute) or smaller (i.e. with Reverse Osmosis or the Caware 0.1 Micron Absolute 3-in-1 Sediment, Chemical + Bacteria Reduction Filter). Such fine filtration, used along with regular sanitation (i.e. with HydroSil Ultra 7.5%) is a cost-effective and safe drinking water solution for rain water and potable bore water*, and is perfect for casual disinfection requirements such as when travelling in a caravan.

Why UV Disinfection is NOT Recommended for Travelling/Casual Use

You may have read that Ultraviolet (UV) Disinfection is one of the safest and most effective methods for treating drinking water, as it has a minimal effect on drinking water’s composition and taste, whilst killing 99.9% of microbiological contaminants. It's true that UV is highly effective at inactivating the DNA cells of water-borne micro-organisms such as bacteria and viruses, and is excellent at killing chlorine-resistant parasites such as Giardia and Cryptosporidium.

However, as effective as they are, please note that UV systems are generally NOT recommended for caravanning and casual use, for the following reasons:

  • UV Systems require electrical input and typically need to be left on 24/7 to prevent degradation of the UV lamp (not ideal for infrequent use).
  • UV radiation also heats up the UV chamber and, in some cases, requires a constant flow of fresh water and a thermal release valve to release the hot water (which is not ideal on a small water tank).
  • UV Systems also contain fragile glass components (not ideal for travelling).
System Dimensions

Length: 34cm 
Compressed width: 15cm


Feed Water Conditions*

  • Pressure: 50 - 100 psi
  • TDS: <1,000 mg/L
  • Hardness: <250mg/L
  • Iron: <0.02
  • Manganese: <0.01
  • Temperature: 1°C - 26°C
  • Flow Rate (Inlet): 1L/Min

RO Performance:


Inorganic Organic Rejection Aluminum 98% Adrazin Over 98% Arsenic 98% Aldrin Over 98% Benzene Over 98% Barium 95% Chlorine Over 98% Cadmium 95% Chloroform Over 98% Calcium 98% DOT Over 98% Chloride 95% Dichlormethane Over 98% Chromium VI 98% Endrin Over 98% Copper 98% Fluoranthene Over 98% Fluoride 99.9% Herbicides Over 98% Iron 98% Lindane Over 98% Lead 98% Methoxychlor Over 98% Magnesium 98% PCB Over 98% Manganese 98% Pesticides Over 98% Mercury II 85% Perchlorethylene Over 98% Nitrate 90% Phenole Over 98% Potassium 95% Tannic Acids Over 98% Selenium IV 95% Toxaphene Over 98% Silver 98% Trichlorethlene Over 98% Sodium 95% Trihalomethanes Over 98% Strontium 98% V.O.C.'s Over 98% Sulphate 98% Total Dissolved Solids 95% Zinc 98%


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.