4 Stage Reverse Osmosis Under Sink Unit Standard Model 021-4S

200 litre per day genuine Dow Filmtec membrane @50 psi, 300 litres @ 87 psi. LOW WASTE 1.25 to 1

All components are Australian Standards and or NSF certified.

Plymouth style quality housings, Certified Australian Standard AS 3497

Optional with in-line re-mineraliser (ALKALIZER) making it a 5 stage extra $30.00

Replacement trio of cartridges (ROCDU-01) which is the annual change are $58.00 but are offered at a 20% discount if ordered with the main unit ($46.40)

See faucet (tap) range, click here to view.

Removes up to 98% of Fluoride, Substance treatment rates for TFC reverse osmosis, click here for a full list in PDF. 

1 Micron food grade polyspun sediment filter 9 ¾" (248mm) (standard size)

CTO/2 quality carbon cartridge 9 ¾" (248mm) 22,500 litres chlorine rating

Genuine Omnipure CL10RO- high purity carbon post filter.

Genuine Dow Filmtec TFC Membrane (standard by which all other membranes are measured)

Main filter unit size, 42 cm high, 35 cm wide & 14 cm deep.

9 litre stainless steel storage tank (exceeds drinking water guidelines) NSF Certified. If space is an issue we also offer a 4.2 litre or 12 litre tank, click here for tank details.

Installation phone help line if needed open 7 days a week and 14 hours a day

Standard type flow restrictor

Installation choice 1/2" tee olive fitting, 3/4" dishwasher adapter or 1/2" easy fit braided line flick mixer adapter, our systems take the average handyman 1/2 to 1 hour to install

Mains connect systems click here to view how each are installed water filter parts

600 kpa pressure limiting valve, touch flo style dedicated faucet

This Reverse Osmosis system was originally developed to compete directly with the Chinese imported systems.

At first we tried the same components as they use but with better Taiwanese housings and American cartridges, but some of the components during testing failed.

First we up-graded the auto shut off valve to the U.S.A. made Hydromatic valve which has proved to be very reliable as well as the Hydromatic check valve, we then found the Chinese copy of the Jaco fittings to also be of poor quality and subject to blow off so we up-graded them to the genuine Jaco gripper series which never let go, then it was the tubing that we up-graded to the genuine British John Guest tubing which is extremely high quality, next was the Faucet, we purchased some of the non NSF faucets to supply with the system but with between 6 to 11% lead content in the brass the faucet was made from the water had a metallic taste when first used after sitting say overnight so we tossed those faucets in the garbage and purchased NSF no lead faucets to supply with the systems, so in the end we found that we had a system that was reliable but costs more to produce than the Chinese systems.

The PSI-021-4S may not be as cheap as the Chinese systems but we could not sell a system that would have been a problem for our customers as well as being a warranty nightmare for us.

In the end the PSI-021-4S Undersink reverse osmosis system is good quality, is reliable, suits those looking for a budget system without running the risk of buying a system that will give them problems, the price doesn’t match the Chinese systems but we would rather miss a sale than sell something that would fail. product comes complete, ready for installation.

All reverse osmosis systems require a minimum pressure of 40 psi (280kpa) with 50 psi (350kpa) or more is ideal. If you are unsure what your pressure is check with your local Council or water authority.

Substance treatment rates for TFC reverse osmosis, click here for a full list in PDF.