I bought this item based on a lot of positive online reviews. I was very excited to get it up and running. There was a little hiccup when I first installed my system. My source water is very high in TDS -- around 500 ppm. Once it was fully installed and I did all of the necessary flushes, the unit was only reducing the TDS to around 400 ppm. Something was wrong and I couldn't figure out what since I followed the directions precisely. Hydro-logic makes it abundantly clear to contact them if you have any issues whatsoever, and that's exactly what I did. I spoke to Dan. He was sure that there was something wrong with the membranes and offered to pay to have the unit returned or to send me two new membranes. Opted for the new membranes. Sure enough, once I replaced the factory membranes my poms dropped from 480 all the way down to 40. I’m not sure what was wrong with the other membranes considering that they didn't look damaged or anything. But it's working and I couldn't be any happier! Thanks so much for your help. It's nice to see such great customer service!