4-Stage Under-Sink Reverse Osmosis System

Enjoy pure, great-tasting water directly from your dedicated faucet with the high-quality 4-stage reverse osmosis (RO) system. Engineered for efficiency and reliability, this system removes contaminants while maintaining a low water waste ratio of just 1.25:1—more efficient than standard RO systems.

Why Choose This System?

The PSI-021-4S Reverse Osmosis System is designed to outperform imported Chinese RO systems without compromising on quality. While it may not offer the lowest price, it prioritises reliability, performance, and long-term durability.

• Compact Under-Sink Installation – Fits neatly under your sink with a dedicated faucet for easy access.
• Advanced 4-Stage Filtration – Utilises high-performance filters to effectively remove impurities.
• Genuine Dow Filmtec Membrane – Industry-leading 200 litres per day at 50 psi (350 kPa), and up to 300 litres per day at 87 psi, for faster refills.
• No Electricity Required – Runs purely on water pressure with automatic shut-off valves and check valves.
• Low Waste Ratio (1.25:1) – Reduces water wastage compared to standard RO systems.
• Auto Shut-Off Function – Prevents unnecessary water waste by stopping flow when the storage tank is full.
• Certified & Compliant – All components meet Australian Standards and NSF certifications (042, 053, 058) for safety and performance.
• Optional Alkalizer (Re-Mineraliser) – Restores essential minerals and balances pH to neutral, counteracting the natural acidity of RO water.

How It Works: 4-Stage Filtration Process

• Stage 1: 1-Micron Food-Grade Sediment Filter (U.S. Made) – Removes dirt, sand, and other physical particles.
• Stage 2: Omnipure Coconut Carbon Block Filter (U.S. Made) – Reduces chlorine, chemicals, and odours. Rated for 37,000 litres of chlorine removal.
• Stage 3: Reverse Osmosis Membrane (Dow Filmtec – U.S. Made) – Removes 96-98% of fluoride, heavy metals, and other impurities. The industry-standard Thin Film Composite (TFC) membrane ensures only pure H₂O molecules pass through.
• Stage 4: Omnipure Coconut Carbon Post-Filter (U.S. Made) – Further purifies water, improving taste and removing organic compounds.
• Optional Alkalizer (Re-Mineraliser) – Uses crushed marble and limestone to restore essential minerals and neutralise acidity.

System Specifications & Features

• Premium Components – Includes a 550 kPa pressure-limiting valve with dual check valves (Watermark certified: AS1357-2, Licence No. 23133).
• Installation Options – Choose from ½” tee olive fitting, ¾” dishwasher adapter, or ½” easy-fit braided line flick mixer adapter.
• Easy Installation – Designed for the average handyman, installation takes 30-60 minutes.
• Minimum Required Pressure – 40 psi (280 kPa) (50 psi/350 kPa or higher is ideal).
• Main Filter Unit Size – 42 cm high × 35 cm wide × 14 cm deep.

Storage Tank Options:

• Standard: 9L stainless steel tank (NSF Certified, exceeds drinking water guidelines).
• Alternative tank sizes available:
  • 4.2L: 33 cm high × 20.5 cm diameter
  • 9L: 39 cm high × 24 cm diameter
  • 12L: 39 cm high × 27.5 cm diameter

Replacement Cartridges & Maintenance

• Annual Cartridge Pack – Click here to order.
• Reverse Osmosis Membrane (Replaced every 4 years) – Click here to order.
• Re-Mineraliser Cartridge (If fitted, replaced every 2 years) – Click here to order.