Backflushing made it worse, for some reason. I went through a membrane in 6 weeks, then in 4 weeks when I was backflushing.

It was getting worse and worse. I called Kent Marine(the manufacturer) to ask why, and if I was doing something wrong. I went through the process, step by step, over the phone. I called back the second time and asked for a supervisor. He told me to stop backflushing because I was most likely "purging some really bad stuff back through the membrane and it's sticking there." Since I stopped backflushing, the membranes last around 6 months(I test with an electronic monitor). I found another manufacturer(Pinnacle? or somebody else?) who doesn't recommend backflushing at all. Go figure. Maybe it depends on the baseline condition of the water. Just a guess. I do know that these units are tested in ideal conditions. I think this may give misleading results as to how long components last. Mexico City sounds like an ideal testing ground.

Amanda