Learn about reverse osmosis water filters from Peter Howard.
The reverse osmosis water filter is available on the market in a wide range of styles and quality. The strength of the housings in a reverse osmosis water filter systems is more important than with a straight carbon water filter system, because the reverse osmosis water filter operates at a higher pressure. The typical pressure limiting valve used in reverse osmosis Undersink systems is usually 500 to 600 KPA (72 to 87 psi) which applies a considerable strain on the housing. Undersink reverse osmosis water filters therefore have an auto shut-off valve and a non return valve, these components work together to turn the in-feed water supply off when the back pressure from the storage tank equals about 66% of the in-feed pressure, this auto shut-off system is an important component of an undersink reverse osmosis.
The membranes in our water filter systems are the Dow Filmtec brand, Dow Filmtec is the industry leader due to their faster flow rate at lower pressures, higher rejection rates and longer lasting often as much as 2 to 3 times as long. The Dow Filmtec membranes are a TFC (thin film composite) membrane that has a reputation for resistance to bacteria and chemicals, the domestic membranes come in 140, 200, 300 and 400 litres per day production, these ratings are done at 350 kpa (50 psi) pressure at 25 degrees water temperature. If the pressure is higher the production rate is faster and if water temperatures drop below the 25 degrees the production rate will slow.
The sediment pre-filter removes things like sand and fine sediment, we use the Purtrex 1 micron polyspun sediment cartridge, these filters are manufactured by GE Osmonics in the U.S.A. which is the largest non Asian manufacturer in the World.
The carbon pre-filter is required when the water being supplied to the unit is chlorinated as chlorine can damage the membrane. Dow Filmtec membranes are tolerant of about 1 gram of chlorine before it starts to damage the membrane, 1 gram doesn't sound like very much but the chlorine injected into mains water supplies is a gas not a liquid so 1 gram is a lot, the carbon pre-filter removes the chlorine that could damage the membrane, the carbon pre-filter in most of our units is the Matrikx CTO/2 which is a 5 micron extruded carbon block filter cartridge made by KX Industries in the U.S. KX Industries is the largest manufactured of this type of cartridge in the World.
The 12 litre tank (usable volume) is made of 304 stainless steel anywhere the water can touch metal. The company that makes these tanks make an unbelievable 80,000 reverse osmosis storage tanks a day.
The housings (Premium Systems) are made by Pentek which are made in Sheboygan, Wisconsin, U.S.A. The housing we use in the premium system is model number 158179 which is a full skirt ¼" ported 10 inch (9-3/4") housing. The housings for the standard systems are made in Taiwan by Aquapro.
With our reverse osmosis water filters we also include a long-reach, lead-free water filter faucet manufactured by Tomlinson in the U.S. which is made from Stainless Steel (Premium Models). The lead free long reach faucet supplied with the Standard systems is made by Easywell in Taiwan. There are other models of faucets available as an up-grade, some are a little extra.
When you buy a reverse osmosis water filter from us we include all the component parts, including fittings, an automatic shut-off valve, inlet and drain saddles, and 8 metres of tubing. We also send you a set of installation instructions.
42: Drinking Water Treatment Units:
53: Drinking Water Treatment Units:
58: Reverse Osmosis Drinking Water Treatment Systems
NSF stands for National Sanitation Foundation which is a non profit organization that operates world wide, it is the Worlds leading certification authority for food products.
The NSF standard 42 is to certify that the materials that the item is constructed from doesn't contain any contaminating chemicals and the like.
NSF standard 53 is for certification for Cyst removal like Giardia and Cryptosporidium, a cartridge that is rated for Cyst removal and NSF listed will remove Cysts.
NSF standard 58 is to certify the system is reverse osmosis, not all membranes are in fact reverse osmosis, sometimes you will find membranes offered that are low pressure operating down to as low as 20 psi, these are not reverse osmosis membranes but Ultrafiltration membrane, the membranes we sell are all reverse osmosis membranes to NSF standard 58.