Buckeye Hydro
.Registered Member
So you got about 5 months from the DI cartridge - that's not necessarily unusual, depending upon the tds of your RO water and how much DI water you make.
If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block filter (collectively called prefilters) do very little to remove dissolved solids. So with your tap water at (for example) 400 ppm, you can measure the water at the “in†port on your RO housing and you'll see its still approximately 400 ppm.
The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 90% (i.e., they reject 90% of the dissolved solids in feed water). So the purified water coming from your 100 gpd membrane would be about 40 ppm (a 90% reduction). Filmtec 75 gpd (and below) membranes produce less water (aka “permeateâ€Â), but have a higher rejection rate (96 to 98%). The life span of a RO membrane is dependant upon how much water you run through it, and how dirty the water is.
Membranes can function well for a year, two years, or more. To test the membrane, measure the total dissolved solids (TDS) in the water coming in to the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membrane’s advertised rejection rate, and to the same reading you recorded when the membrane was new. Membranes also commonly produce less water as their function declines.
After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the 40 ppm water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm to 3 ppm, 5 ppm, and higher, you know that your resin needs to be replaced.
Sometimes people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane, or a membrane that is not fully seated, or an RO membrane housing that is cracked - each of these conditions will result in the DI stage receiving “dirty†water. This will exhaust the resin quicker then would otherwise have been the case. Sometimes the problem is poor quality resin, or resin that was not stored properly before use.
What is the tds of your tap water and your RO water?
Russ
If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block filter (collectively called prefilters) do very little to remove dissolved solids. So with your tap water at (for example) 400 ppm, you can measure the water at the “in†port on your RO housing and you'll see its still approximately 400 ppm.
The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 90% (i.e., they reject 90% of the dissolved solids in feed water). So the purified water coming from your 100 gpd membrane would be about 40 ppm (a 90% reduction). Filmtec 75 gpd (and below) membranes produce less water (aka “permeateâ€Â), but have a higher rejection rate (96 to 98%). The life span of a RO membrane is dependant upon how much water you run through it, and how dirty the water is.
Membranes can function well for a year, two years, or more. To test the membrane, measure the total dissolved solids (TDS) in the water coming in to the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membrane’s advertised rejection rate, and to the same reading you recorded when the membrane was new. Membranes also commonly produce less water as their function declines.
After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the 40 ppm water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm to 3 ppm, 5 ppm, and higher, you know that your resin needs to be replaced.
Sometimes people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane, or a membrane that is not fully seated, or an RO membrane housing that is cracked - each of these conditions will result in the DI stage receiving “dirty†water. This will exhaust the resin quicker then would otherwise have been the case. Sometimes the problem is poor quality resin, or resin that was not stored properly before use.
What is the tds of your tap water and your RO water?
Russ
