Direct Flow 4-Stage Reverse Osmosis 100-Gallons-Per-Day (US Gallon) Water Filter System including DI Resin Stage

4 Stage reverse osmosis system with DI resin stage for aquariums, drinking water, pharmaceuticals, plant propagation and window cleaning.

£94.15 £78.46
In stock

;"Vyair direct-flow 4-stage RO filtration system suitable for under sink point-of-use installation provides a continuous supply of clean, fresh drinking water. Water after it has been passed through an RO system has a reduced pH*. It is also an excellent source to prepare appropriate conditions for aquatic organisms.

This system includes a 5 micron-rating sediment filter cartridge made from spun polyester, which effectively removes particulates including sand, silt, rust, suspended solids, etc., followed by an activated coconut extruded carbon block which removes chlorine, pesticides and dissolved organic compounds. An RO membrane is placed after the filters and this is where the main filtration takes place, removing 96%-99% of all contaminants from the water, including bacteria and viruses (0,0001 μm and larger). Waste water is poured into the drain.

This system is also equipped with a final ‘POLISHING’ stage, provided via mixed-bed ion-exchange resin. It consists of a carefully blended mixture of virgin raw materials, strong acid cation and strong base anion resins. It is widely recommended for all non-regenerable mixed-bed applications where reliable production of the highest quality water is required, and where the resin must have an absolute minimum of ionic and non-ionic contamination before it is used. Any pre-contamination in the resin will reduce its overall lifespan, so a high quality resin will last longer.

Our MB-115 mixed-bed formulation is regarded by all in the water purification industry as the best performing mixed-bed de-ionisation resin available, consistently out-performing every other brand, pound for pound. Optional upgrade: colour-change resin turns from green to yellow when it has expired, meaning you have a visual indicator of when your resin will need replacing. Ordinary resin usually requires to be checked with a TDS meter, however colour-change resin means you can tell at a glance when it is time to renew the resin.

The RO-100M is an upgraded version of the RO-100. The main difference between these two units is that the RO-100M is equipped with an auto shut-off valve to eliminate waste water by closing the feed line when the tank is full, as well as a larger DI resin stage. In order to look to extend the life of the reverse osmosis element we have also incorporated a manual flush valve on this unit. This will enable you to open the flush tap and allow a high pressure flow of water to go across the membrane and flush away accumulated impurities.

This reverse osmosis water filter, like all unpumped reverse osmosis water filters, does rely on you having a strong mains water pressure. Please do not buy this item if you do not have a good water pressure. This unit operates best at input water pressures of between 30psi (2 Bar) and 60psi (4 Bar). We would suggest that this is not suitable for use with gravity fed unpumped cold water systems (where the water is stored in the loft). Normal UK water pressure should start from around 2 bar or above.

Our 4-stage system is offered as a complete set with filter cartridges, RO membrane, additional accessories and valves preventing the membrane from becoming dried out.

*pH of water after RO system depends on source water.

System specifications:

  • Connection adapter: 1/4”
  • Working Temp.: 2°C - 45°C (35ºF - 113ºF)
  • Operating Pressure: Max. 6.0 bar (90 psi) Min. 2.8 bar (40 psi)
  • Typical Rejection Rate: 99.99% TDS (Total Dissolved Solids)
  • pH Parameters: Maximum 6 / Minimum 1
  • Iron: Maximum 0.1 ppm
  • TDS (Total Dissolved Solids) < 900 ppm
  • Turbidity < 2 NTU
  • System dimensions: (H x W x L) 370mm x 472mm x 170mm

Complete package contains:

  • The Vyair direct-flow 4-stage comes complete with the following cartridges: PP, CTO
  • RO membrane element type: MR-1812-100 (low pressure)
  • Manual flush tap to clean RO membrane, 10" transparent housing for DI resin chamber
  • 1 litre MB-115 mixed-bed de-ionisation resin (optional upgrade for colour-change resin)
  • Feed water connector: (can be fitted to copper mains water pipe)
  • 1/4" tubing for system connection (5 metres)
  • FDA certified filter housings, spanners for filter and RO housings
  • Auto shut-off valve to reduce waste water, roll of PTFE tape
  • 100% sterilized and manufactured in compliance with NSF Standard No.58
  • Boxed and factory tested
  • Completely assembled and ready to use
  • Full instructions


  • 1) PP. 10" sediment cartridge (pre-filter) melt-blown polypropylene. 5 micron sediment filter traps dirt, sediment, rust and other particulate matter.
  • 2) CTO. 10" coconut shell carbon cartridge (pre-filter). Activated carbon block filter is used to reduce chlorine, colour, taste, odour and other organic impurities.
  • 3) MR-1812-100. Thin film composite reverse osmosis membrane (100 US Gallon per day), 0.0001 micron. Semi-permeable membrane removes salts, minerals, metals, bacteria, viruses, cysts, TDS, hardness, fluoride, pesticides, lead, mercury, cadmium, arsenic and more. Due to the time needed to remove all these ingredients we recommend purchasing a water storage tank with your RO system.
  • 4) MB-115. Mixture of cation and anion de-ionisation resin combined in a 40/60 blend. Mixed-bed demineralizer is used for final water polishing to clean the last few ions within water prior to use. A single pass through a mixed-bed ion-exchange column results in the purest that can possibly be made.

IMPORTANT: Do not use with water that is microbiologically unsafe or of unknown quality without adequate disinfection before or after the system. Water filtration systems can help reduce the presence of contaminants. In addition, some water filtration systems can help reduce the presence of micro-organisms or other contaminants that pose potential health risks. Regularly scheduled maintenance and replacement of the filter cartridges is recommended in order for the product to perform as specified.

Replace the filter cartridges at least every 3 or 6 months (depending on water quality).

Replace the RO membrane every 2 to 3 years (depending on water quality).

LIMITED WARRANTY: VYAIR warrants that this product is free from defects in materials and workmanship. This warranty, together with any and all warranties implied by law, shall be limited to a period of one (1) year from the date of original purchase. This limited warranty does not apply to failures that result from abuse, misuse, alteration or failure to properly comply with installation, or cartridge change instructions. VYAIR strongly recommends adding to all point of use filtration systems a Pressure Limiting Valve (call for further details) to guard against unwanted extreme water pressure events, pressure increases, surges, and water hammer which could occur in the water pipes. Not having one installed could mean that if you ever did have to claim damage caused by a burst water filter system, your claim could be denied.

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