Bests & Worsts Reviews from Amazon

There's a major problem with these reverse osmosis systems, a dirty little secret that no one seems to discuss. I knew there was something wrong when we discovered our tea kettle becoming heavily calcified with water from the filter. To determine what was happening, I purchased and installed an HM Digital TDS meter with two inline sensors to check water quality from the reverse osmosis output and from the remineralization filter output. What I discovered was a shock. Basically, if you let the system sit unused for any period of time, the water impurifies inside the reverse osmosis filter due to waste water flowing across the membrane in the wrong direction. Secondly, when water sits inside the remineralization filter, which has a large volume in this case, it becomes heavily mineralized. The taste is ruined, and frankly, the whole reason for having the reverse osmosis system in the first place is negated. It's almost like these under-sink systems are just there to make you feel good about drinking bad quality water. It's like a placebo. For the system to function optimally, stale water in the system has to be flushed down the drain prior to every use. This seems terribly inefficient, and it makes the system not work on-demand. In my case, it took about 80 seconds of flushing before TDS readings reached the optimal level. My tap water had a TDS of around 480 PPM. After filtration through the carbon filter and reverse osmosis membrane, it came out at about 8 PPM. That's about 98.4% filtration of dissolved solids, which seems pretty good. Once the water passed through the remineralizing filter, it was about 20 PPM TDS. Alkalinity was restored and a few minerals added to make the water healthy for consumption. Again, this seems a good result. But without flushing, TDS output from the RO filter sometimes rises as high as 250 PPM in the first few seconds. And that water hits the remineralization filter and picks up a bunch of solids there, bumping it to 300 PPM, at least for a few seconds. Again, it takes about 80 seconds to normalize and flush out the impure, stale water. It's almost as bad as drinking water straight from the tap. The same problem would likely affect systems with a tank as well. Water already in the tank would regularly be fouled with impure sitting water from the reverse osmosis filter. It's a fatal flaw of these residential reverse osmosis membranes and remineralization filters. The end result is this: if want quality filtered water, you have to flush the system for about 80 seconds PRIOR TO EVERY SINGLE USE. It would be better to filter water once a day into a secondary holding tank, after running a flushing cycle, and use it from the tank over the course of the day.