Iv got a pure freedom ro , got the membranes from daqua, filters from gardiners and 1ltr di from pure freedom, it's comes out of the RO at 002 then goes through resin , that's what I don't get why it's only lasting a week
Even when my 40 40 ro is new it still comes out between 25 to 30 b4 resin but I always get three months out of my 6l bottle before having to change resin
Colin,
Something is very wrong with your system, a 4040 membrane should last 5 years, they fail because the tiny holes in the membrane break down ( get wider) or get blocked.
Possible causes.
Putting too much pressure on the membrane, closing off the waste too much.
RO shock which is caused by applying the pressure to quickly onto a dry membrane.
Chlorine getting to the membrane.
Sediment getting to the membrane.
Some sort of bacteria or growth in the membrane vessel, needs disinfected before the next membrane change.
Not enough water pressure to start with causing the tds to rise quicker than it should as the membrane gets older, which is my
hunch on what your problem is going by the new membrane TDS readings.
Either way at £250 a year to change I would be looking at getting this sorted.