JG1
03/11/2004, 11:39 AM
What do you guys think of this posted on the airwaterice site? About not using a .5 mocron prefilter.
http://www.airwaterice.com/Filter%20array.htm
"The idea behind an array of filters is to provide for optimum pressure and long filter life. The pre-filter micron rating required to optimize the life of a Reverse Osmosis membrane is Five (5) micron. No manufactures asks for more protection than that and nothing is gained by smaller micron filters. In fact you only hurt the overall performance of the system. How do you hurt it? By causing excessive pressure drop. Never install .5 one half micron filters as pre-filters. Now a filter array is designed so that each filter in turn does the work required of it and protects the next filter in line. It would make no sense to dump big particles of dirt on a fine filter. You just load it up immediately causing a great deal of pressure loss. What I now recommend is this. Get a ten (10) micron sediment filter for your first stage, no less. Than obtain a good quality five micron (5) carbon block acid washed for the second stage. Now the ten micron filter has removed all of the dirt and sediment over ten microns in size from the water, protecting the five micron filter. Now all the five micron filter has to remove is sediment between 5 and 10 micron. In the third stage get a quality one (1) micron carbon filter or a sediment if you have well water.. You have accomplished filtration down to one micron, five times the manufactures requirements. You have not lost a great deal of pressure and the filter can now provide you full service. So to recap the ten protects the five, the five protects the one, and the one micron exceeds the requirement to protect the membrane by a factor of five. So your membrane sees only one micron sediment one fifth the requirement. Well protected by 10 - 1 micron array the membrane is free to go about the task of removing bacteria, virus, salt, ions, dissolved metals (TDS). The filters alone have no impact on the TDS and should never be relied on to remove bacteria . Ions and bacteria are best left to the membrane After the work done by the pre-filters and the membrane, your water is very pure. The final stage is D.I. A typical mixed bed D.I. cartridge is capable of reducing the T.D.S .to -0-. It kills me to see anyone recommend a (1) micron filter in the first stage."
http://www.airwaterice.com/Filter%20array.htm
"The idea behind an array of filters is to provide for optimum pressure and long filter life. The pre-filter micron rating required to optimize the life of a Reverse Osmosis membrane is Five (5) micron. No manufactures asks for more protection than that and nothing is gained by smaller micron filters. In fact you only hurt the overall performance of the system. How do you hurt it? By causing excessive pressure drop. Never install .5 one half micron filters as pre-filters. Now a filter array is designed so that each filter in turn does the work required of it and protects the next filter in line. It would make no sense to dump big particles of dirt on a fine filter. You just load it up immediately causing a great deal of pressure loss. What I now recommend is this. Get a ten (10) micron sediment filter for your first stage, no less. Than obtain a good quality five micron (5) carbon block acid washed for the second stage. Now the ten micron filter has removed all of the dirt and sediment over ten microns in size from the water, protecting the five micron filter. Now all the five micron filter has to remove is sediment between 5 and 10 micron. In the third stage get a quality one (1) micron carbon filter or a sediment if you have well water.. You have accomplished filtration down to one micron, five times the manufactures requirements. You have not lost a great deal of pressure and the filter can now provide you full service. So to recap the ten protects the five, the five protects the one, and the one micron exceeds the requirement to protect the membrane by a factor of five. So your membrane sees only one micron sediment one fifth the requirement. Well protected by 10 - 1 micron array the membrane is free to go about the task of removing bacteria, virus, salt, ions, dissolved metals (TDS). The filters alone have no impact on the TDS and should never be relied on to remove bacteria . Ions and bacteria are best left to the membrane After the work done by the pre-filters and the membrane, your water is very pure. The final stage is D.I. A typical mixed bed D.I. cartridge is capable of reducing the T.D.S .to -0-. It kills me to see anyone recommend a (1) micron filter in the first stage."