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100 GPD Reverse Osmosis Water Filter System w/ Micro Computer, TDS Monitoring & Auto Flush | 15L/Hr or 375 Litres/Day (GT1-23LS)

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100 GPD Reverse Osmosis Water Filter System w/ Micro Computer, TDS Monitoring & Auto Flush | 15L/Hr or 375 Litres/Day (1-23LS)

The 100 Gallon Per Day Reverse Osmosis Water Filter System is a compact design that includes an inbuilt pressure pump to work on most water sources.

Our RO unit is widely used in commercial water treatment both in the Dental and Medical industries and is commonly used in the food and beverage industry for providing purified water as a base ingredient for alcohol distilling, brewing, and other like-processes. This system comes with your choice of Deionising or Calcite Alkalising post-filter. 

The '0 TDS' Deionising post filter produces absolute pure water with no traces of dissolved minerals, similar to distilled water. This water is required for sensitive medical apparatuses including instrument sterilising. '0 TDS' water also has other uses, for example, in the Aquatics industry. Low EC and '0 TDS' water eliminates the need for expensive chemical treatment or bulk-bought water. It is perfect for water changeover in saltwater aquariums to avoid build-up in salt and mineral hardness. 

With the filter combinations that we elect to use in this system, it has a wide array of uses and can work on low pressure bore water right up to town municipal water supplies. The cartridges used are standard-sized 10" x 2.5" cartridges and can be replaced easily.

**Please note that if you are treating a raw water source such as a bore, creek, dam, river, etc. there are specific inlet water requirements for a reverse osmosis system. If you are unsure about your water source please contact us BEFORE purchasing these systems with a comprehensive water analysis to ensure pre-treatment requirements are met. When treating a raw water source, please note that RO systems are prone to biofouling, you will need to pre-treat the water to ensure biofouling doesn't occur. Failure to do so will void your warranty and render the RO membrane un-salvageable.**

Inlet Water Quality Guidelines (Treated Mains Water)** 

TDS < 2000 mg/L
Hardness < 120 mg/L
Chloride < 500 mg/L
Iron < 0.3 mg/L
Manganese < 0.1 mg/L


Micro-Computer Controller

The micro-computer controller is designed to take the guesswork out of using and maintaining your reverse osmosis water filter. The micro-computer can automatically monitor the TDS of the filtered water to maintain water quality, remind you to replace the pre-filters and membrane at the designated (customisable) times, and display the status of the water filter system (i.e. full, flush, production, source & power).

Working Pressure Gauge

The pressure gauge which is pre-installed at the RO membrane inlet gives users a clear indication of the working osmotic pressure ie. the pressure of the water going through the RO membrane. Working pressure is a simple feedback measure that can is incredibly useful to assist the troubleshooting process (if and when required). 


The rating of this Reverse Osmosis system is 100GPD as per the membrane specifications meaning this system is capable of approx. 0.25 L/Min of water production (note: this will vary depending on water quality and a number of factors). The systems are designed to be run in a closed-loop configuration where the system runs off a float switch or timer. This type of configuration allows for system downtime and helps extend the lifespan of the pump as the system is intermittently producing water.

IMPORTANT: When the system is installed in an open-loop configuration and the pumps haven’t been allowed any downtime (i.e. 24/7 operation), you may expect to see a decrease in the lifespan of the pump. If you intend to use the system this way please contact us as we may have a better solution for your specific requirements.

Production Scenario for Closed-loop Configuration
Example: The system is run for up to 8 hrs a day with a 30 min cool-down period. In this configuration, the system will produce approx. 125L +/- per day. This is the recommended runtime scenario or extended pump lifespan, as specified by the manufacturer.

Production Scenario for Open-loop Configuration
Example: The system is run continuously without a cool-down period. In this configuration, the system will produce approx.  *375L +/- per day. You will also need to factor in the auto-backflush cycles for this unit every 30 min. *This is the maximum capacity of what this system can produce, however, this may also decrease pump lifespan.

*Note: The pump comes with a 90-day replacement guarantee/12 month pro-rata warranty per pump, from the date of invoice. If the pump fails within the first 90 days of operation, we will replace it. If it fails from 90-365 days, we will cover it on a pro-rata basis. The pumps, as well as the filters, are classed as consumable items.

Post-Filter Options

The post-filter is a very important part of reverse osmosis water treatment. The performance of RO membranes in terms of contaminant reduction is similar across the board, so it is in fact the post-membrane filter that differentiates various RO systems. Your choice of post-filter will depend on the application. 

Reverse Osmosis on its own will generally produce mildly acidic water which is not ideal for straight drinking without further treatment. For applications where drinking water is required, select the Alkaline Post Filter option, which uses Calcite to buffer the pH to between 7pH and 8 pH.

However, when the water is required to have a TDS reading of 0, we use a DI Resin cartridge. DI resin will remove any remaining trace minerals or salts in the water leaving the water as pure H2O. This type of water is required for many applications such as in the Dental/Medical Industries, Aquariums, and any other applications that require "0 TDS" or distilled-quality water.

Filter Breakdown

Stage 1: 5 Micron Polypropylene Spun Sediment Filter - Replace every 6 months

Poly Spun filters are an economical option for water filtration. We use them in this system to protect the RO membrane and carbon pre-filter from clogging and damage caused by excessive sediment. 

Stage 2: Granular Activated Carbon Filter - Replace every 6 months

Our Granular Activated Carbon is manufactured from coconut shell and features a high density, large micro-pore volume, and high surface area. It is commonly used for the purification of potable water, beverage manufacture, dialysis, aquarium water, and a variety of food-grade applications. In properly designed systems, will effectively remove chlorine, chloramines, tastes, odour, and more. 

Stage 3: 5 Micron Coconut Carbon Block Filter - Replace every 6 months

The perfect carbon block filter is made from 100% Coconut Shell Carbon, which creates what many believe to be the sweetest-tasting water. The unique pore structure of this carbon is well suited for chemical absorption, including VOC’s, while reducing chlorine and chemicals that contribute to taste and odour.

Carbon filtration is the best form of filtration for chemical extraction due to a longer and more thorough contact time, which in turn provides an extremely comprehensive method of chemical removal. We HIGHLY recommend this method of filtration for chemical taste and odour extraction.

Stage 4: 100GPD Reverse Osmosis Membrane

The Reverse Osmosis Membrane is the workhorse of any RO system. It is constructed from a wrapped semi-permeable membrane material that uses pressure to separate impurities such as ions, metals, minerals, salts, and other large molecules from the water, carrying them to waste.

*Reverse Osmosis membranes do not have a set replacement schedule, due to the variables that can make the membrane filter life vary significantly. This is mostly due to incoming water quality, which differs from town to town, and state to state. Instead of relying on guesswork, the GT1-23LS RO system is fitted with a micro-computer that can detect the TDS of post-membrane filtered water, and will alarm when the membrane requires replacing. This system is set to 40 ppm TDS as a default, however, this can be easily modified based on your needs.

TDS meters measure the total dissolved solids in ppm in the water. To test your membrane, get a baseline reading out of your tap (unfiltered water) and then compare that to a reading directly off the membrane (disconnect the tube before it goes into the post filter cartridge). You can expect to get a difference of approx 90-99% between the readings which indicate that the membrane is functioning correctly. If this % is beginning to drop below 90% it suggests that the RO membrane requires replacement.

Stage 5: Post-Filter

(Option 1) GAC + Calcite Alkalising Filter - Replace Every 6 - 12 Months Depending On Usage

When this system is used for drinking water applications we always recommend the use of a pH-neutral post filter. When the water comes out of the RO membrane, the water will have little mineral content causing the pH to drop well below 7 pH. Drinking water should be no lower than 6.8 pH.

When the alkaline filter is selected, there will be no stage 5 mounted on the top bracket, rather we will supply a separate 10" filter system to be connected for the final stage of filtration.

(Option 2) Deionising (DI) Resin Filter - Up to 12 Months*

The canister DI filter will replace the existing GAC inline filter. Due to the size of this filter housing and canister, it will need to be mounted separately from the RO unit. We will provide an inline tube joiner so you can join the RO system to the DI canister.

(Option 3) No Post-Filter

Storage Tanks

When required, we can design these systems to allow pressurised storage tanks. These tanks will provide you with a higher volume of water on-demand, allowing you to provide water to appliances quicker for longer periods of time. For example, a coffee shop may only require 100L water per day, but it is all in a 3 hour period. The use of a storage tank provides this upfront water capacity, while the system works to produce more water.

The storage tanks will only be able to produce water to the tap/machine as fast as the final filter cartridge allows. For example, a standard GAC filter will only run at 3-5L per minute and as previously outlined, a DI resin cartridge works better the slower it goes. This will need to be taken into account when comparing specifications and requirements from your appliance.

Tank Dimensions

6L Tank
Tank Height: 27cm
Tank Width: 20cm
Connection: Top Mount 1/4" Male (Allow 2" for valve)

8L Tank
Tank Height: 42cm
Tank Width: 23cm
Connection: Top Mount 1/4" Male (Allow 2" for valve)

12L Tank
Tank Height: 42cm
Tank Width: 29cm
Connection: Top Mount 1/4" Male (Allow 2" for valve)

38L Tank
Height of Tank: 58cm 
Width of Tank: 40cm
Connection: Bottom - Horizontal 1" Female to 1/4" Reducer

76L Tank
Height of Tank: 78cm 
Width of Tank: 40cm
Connection: Bottom - Horizontal 1" Female to 1/4" Reducer

System Dimensions

Depth: 25 cm
Width: 36 cm
Height: 46 cm

More Information
Type Water Filter

Working Specifications:

Max Pressure             125 psi
Working Pressure       70psi (500 kPa)
Max Permate Flow      2L/Min
Temperature              1°C – 40°C

Inlet Water Quality Requirements:

TDS                          < 2000 mg/L
Hardness                  < 120 mg/L
Chloride                    < 500 mg/L
Iron                          < 0.3 mg/L
Manganese                < 0.1 mg/L

Micro-Computer Panel Instructions:

Power Light:                Light is on when there is power to the system
Source Light:               Light is on when water supply is on; Light is blinking when there is no water supply.
Produce Light:             Light is on when system is producing pure water.
Flush Light:                 Light is on when system is in Automatic Backflush Mode.
Full Light:                    Light is on when the circuit is closed; Or if Storage tank is full
Light 1:                        Light is blinking when filter 1 is due for replacement
Light 2:                        Light is blinking when filter 2 is due for replacement
Light 3:                        Light is blinking when filter 3 is due for replacement
Light 4:                        Light is blinking when 4x RO membranes require replacement
Light 5:                        Light is blinking when Post (Final) filter requires replacement
Setup Button:              Used to modify settings on Micro-Computer ,Change filter times and TDS Setting
^Zero Button:              For resetting filter change reminder & adjusting filter change times and TDS Setting
TDS Display:               Shows TDS of pure filtered water, shows Replacement time and TDS setting
OK Light:                     Light is on when TDS is below set value – System operating correctly.
Over Light:                  Light is on when TDS is above set value – Change Membranes

Micro-Computer Functionality Instructions:

  • After completed installation, the LED will show 8ppm (pre-set). The OK Light will be on. The pumps will begin working and the system will start to produce pure water. After 4 minutes of run time, the micro-computer will display the current TDS reading.
  • When the Storage tank is full OR the system becomes a closed circuit (by turning off the outlet line using a tap), the TDS will stop detecting. The Full light will come on, then the system will trigger an automatic flush lasting for 30 seconds. During this flush cycle, you must maintain inlet (source) water so the system has a supply of water for flushing. During this period the flush light will be on.
  • When the Storage tank is empty OR the System becomes an open circuit (by opening the outlet valve or tap) the high-pressure switch will be delayed for 25 seconds before starting the flush process, then will begin to produce pure water. The high-pressure switch will be switched on and off which will cause the electromagnetic valve to open and shut (this will make an audible noise).
  • When the source (influent) water is stopped, the low-pressure switch will delay for 10 seconds before triggering the system to shut down. This delay prevents over pressurisation when the flow rate is insufficient. To prevent such things from happening, the low-pressure switch will turn on and off triggering the solenoid valve to do the same (this will make an audible noise). During this delay period, if the influent water is turned back on, it will cancel the shut off process. When the influent water has stopped, this will also cease the TDS from being detected. The TDS will resume reading after 4 minutes of run time.

How to Preview Default Settings:

  • First, press and hold the Setup button for 2 seconds, this will display the first setting mode. The LED will show 103 and light 1 will begin to blink. Factory settings are 103 which indicate that the first filter replacement is sent to alarm every 3 months. The first digit signifies the filter number and the last 2 digits signify the month.
  • Press the Setup button to bring up the filter 2 timer. It will show 206 and light 2 will blink.
  • Press the Setup button to bring up the filter 3 time. It will show 306 and light 3 will blink.
  • Press the Setup button to bring up the filter 4 time. The LED display will show 040 and light 4 will begin to blink. 040 indicates the TDS limit of the RO membranes. This means when the TDS is above 40 ppm, the replacement change light will blink and the membranes will require replacement.
  • Press the Setup button to bring up the filter 5 time (post filter). It will show 512 and light 5 will blink.
  • If you want to return to original settings, hold the Setup button again for 2 seconds and wait for the “Beep, Beep”.
  • If you need to change multiple settings, do them all in sequence then press and hold the Setup Button for 2 seconds and wait for the “Beep, Beep” to complete all the settings.

Changing Micro-Computer Settings:

For applications where the influent water is municipal and free from most sediments, you can extend the replacement warning for filter 1 to 6 months. To do this, enter setup mode and press the ^Zero Key to increase the number by 1 month per press. If you go too far, hold in the ^Zero Key for 2 seconds, this will reset the number to 100 or 200 etc. If you do not confirm the settings by holding down the Setup Button for 2 seconds, the settings will not be confirmed and they will stay the same.

Automatic Reminder Instructions:

When the system is alarming for a filter change, the filter replacement light will begin to flash and the alarm will sound. Each time water production starts, the alarm will sound for 1:30 minutes. This will occur every time until the filter reminder has been reset.

When the filters have been replaced, hold down the ^Zero Button for two seconds until you hear 2 beeps. The filter replacement light will shut off and the timer will reset.

NOTE: When you replace the new RO membranes, the TDS value may be higher than the alarm setting. This is due to the chemical preservatives inside the membrane. After adequate flushing, this sanitiser will be removed and the TDS will stabilise to normal levels. Due to this, the Micro-Computer alarm has a 4-day delay. If the TDS has not stabilised after 4 days, please contact the manufacturer.

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, so as to be able to be re-sold. This policy falls in line with the Australian Consumer Law, which is designed to protect BOTH BUYERS AND SELLERS. 

You may receive a refund or credit of equal amount, less the Restocking/Out-of-Pocket Shipping Expense Fee, if applicable, and any other deductions that are relevant. 

  • 30-Day Returns Policy: Returns will not be accepted without prior approval or after 30 days of the invoice date.

  • Wrongly Purchased Items/Changes of Mind Policy: Wrongly Purchased Items, or Change of Mind Purchases may be returned for a merchandise credit. This applies to, but is not limited to purchases of products that are:
    • The Wrong Size;
    • The Wrong System;
    • The Wrong Replacement Pack;
    • Due to a Change of Mind;
    • Due to Buyer Error, whereby the buyer has failed to conduct proper due diligence (including contacting FSA prior to purchase in order to clarify the relevant technical specifications, compatibility, requirements etc.) to ensure the product purchased from us is the correct product for their requirements.
  • Restocking/Out-of-Pocket Shipping Expense Fees Policy: All returns will incur a 17.5% restocking fee OR an out-of-pocket shipping expense fee, whichever is greater. 
    • This fee is in place to cover the administrative expense incurred in processing the return and/or the out-of-pocket expenses incurred by us in shipping the item to you. FSA may use its discretion to determine the restocking fee. Please note this policy falls in line with the ACL, and is designed to protect us as the seller from losses incurred due to buyer error. This means that you will NOT receive a full refund of the original purchase price - you will bear the cost of shipping the product back to us, and then you will receive a credit equal to the purchase price of the product LESS the Restocking/Out-of-Pocket Shipping Expense Fee. Please refer to our Shipping Policies (below) for further clarification.
    • Low-Value Returns: Please note that with low-value items, sometimes the cost of sending the item back to us may be more expensive to you, than simply keeping the item. For example, let's say you have ordered 3x meters of the wrong-sized tubing for your needs and paid $12.00. If, for example, it cost us $7.69 to send the item to you, and it would cost you $7.69 to send the item back to us, overall you would be $3.38 worse off (due to incurring $7.69 to send the item back to us, and having $7.69 taken out of the credit) than if you had kept the item and re-ordered the correct product for your needs. 

  • Shipping Policies: 
    • Free Shipping Offer: As part of our offer of Free shipping Australia-Wide, FSA reserves the right to select the most cost-effective courier to effect delivery of the product to you. We make no guarantee as to how long an item will take to arrive due to unforeseen circumstances outside of ours/the couriers' control, including but not limited to: Staff Shortages, Supply Chain Demand, Extreme Weather Events etc.
    • Express Shipping Policy: If you require an item on an urgent or Express basis, it is your (the buyer's) responsibility to contact us directly by telephone on [phone removed by eBay] prior to purchase, in order that we may quote you the options available for Express Delivery to your nominated address, and to organise additional payment for this Express Service. Express Shipping is not included in our offer of free shipping - this service will come at an additional cost payable by the buyer. 
    • Late Shipping Policy: Given that we offer the option for customers to organise Express Shipping with us prior to purchase, cancellations or refunds will NOT be issued on the basis of late or delayed shipping where the customer has opted for our Free Shipping offer. If the item (sent via Free Shipping), arrives late and the buyer wishes to return the item on this basis, the buyer will be liable for the cost of returning the product to us and a Restocking/Out-of-Pocket Shipping Expense Fee will be applicable to the return, as per the listed returns policy line items above. The customer will be issued a merchandise credit.
    • Our offer of Free Shipping does not apply to Returns: Whilst we offer Free Shipping, this does not mean that there is no cost to ship the product - obviously, a shipping expense is incurred, and as with all e-commerce operators that offer Free Shipping, the cost of shipping the product from our warehouse to your nominated shipping address is built into the price of the product. The offer of Free Shipping therefore only applies to the act of FSA supplying the product to you, and does not cover the cost of returning the product from the customer to FSA.
    • Returned to Sender Items: In the case of the buyer being unavailable to sign, refusing delivery, or the item being sent back to us for whatever reason, FSA may, at its discretion, pass the cost of the product being Returned to Sender (i.e. being returned back to us), back onto the buyer. Refer to Restocking/Out-of-Pocket Shipping Expense Fees (above).
    • Lost Parcels: If an item is deemed to be LOST IN TRANSIT by the courier, the customer is entitled to a replacement product or refund in line with the ACL. In the case of a replacement product, FSA reserves the right to send the replacement product in line with its Free Shipping offer. If you do require the replacement item urgently, please get in touch with our customer service team directly to organise Express Shipping. 

  • Product Damage & Product Faults: Any damage to products that are not reported to FSA within 48 business hours of receipted delivery is not covered under our transit warranty. Return shipping is to be paid by the buyer to the address provided by FSA. It is recommended that the customer applies a transit warranty to the return freight item/s, in case of damage.
    • Faults: Should the item appear faulty or doesn’t work as described, you must supply written/photographic/video evidence of the fault to us, so that we may assess whether the unit/item must be returned for testing (if requested). If testing is requested, return postage is to be 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 be responsible for the cost of return postage of the product from FSA's premises, back to the buyer. 
    • Minor Damage: Any damages (minor, that can be repaired) will incur a fee, that will be deducted from the total refund which will be equal to the cost of the replacement parts (List Price) and labour charges (if applicable) to repair the system(s). This will be separate from the Restocking/Out-of-Pocket Shipping Expense Fees.
    • Major Damage: 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.

Returns are not accepted on special order items unless the manufacturer allows it. Applicable fees will apply.

If you have any questions about our return policy, please contact us before purchasing. This will also help to ensure you purchase the correct product that suits your requirements.