After repeated pinhole leaks in our 50 year old plumbing, we recently re-piped our entire home with new copper pipe. We also added a water softener and whole-house catalytic carbon filter (primarily to remove chlorine) and the APEC RO-Hi system for our drinking/cooking water. We added a 6th stage calcium carbonate cartridge (APEC's PHPLUSKIT-38) to the 5-stage APEC RO-Hi system to add back some of the "healthy" minerals removed by the water softener.We are extremely pleased with the quality and taste of the drinking water produced by the APEC RO-Hi system. We also ran a line from the APEC RO-Hi to our icemaker and our ice cubes are crystal clear. Total dissolved solids (TDS) in the drinking water from the APEC RO-Hi system are 14 ppm, versus 135 ppm in our regular tap water.As shown in the attached photo, we mounted the APEC RO-Hi system in our basement, immediately below our kitchen sink, where it is easily accessible to check the various water line connections and change filters. Had we mounted the APEC RO-Hi system under our kitchen sink, it would have been much more of a chore to change filters (think hands and knees with head in a cabinet vs standing up in your basement) and the RO system would take up most of the space under the kitchen sink, where, like many people, we have a garbage can and store dish soap, dishwasher pods, scrub brushes, sponges, etc. Mounting the APEC RO-Hi system in the basement also allows one to place a bucket under the unit when changing filters to catch the water that will inevitably spill out when the filter housings are removed. We would strongly recommend mounting the system in a basement if possible.Our only reason for a 4-star (vs 5-star) review is we had to purchase additional tubing for the drain line and water line to the drinking faucet. The 5 ft. lengths of tubing included with the APEC RO-Hi system are not long enough for any location other than under the sink. Given that many people choose to mount the APEC RO-Hi system in their basement, rather than under a sink, we feel APEC should provide tubing in 10 ft. lengths, rather than 5 ft. lengths (especially given the cost of this unit, which is at the high end).Some installation tips:When attaching the Stage 1-3 filter housings, do not overtighten them. Overtightening the housings will compress the rubber gaskets, preventing them from sealing properly and result in leaking.When removing the Stage 1-3 filter housings, open the drinking water faucet to release the pressure in the system. Releasing the pressure in the system makes removing the housings easier. Of course, the water supply to the system should be turned off when changing filters.When connecting tubing to the push-to-connect fittings, make sure the tube is fully inserted. The tube should go in about half an inch or so, and you should hear and feel the tube pop in when it is fully inserted. If the tubing only goes in a little bit, and you don't feel it pop in, it is not fully inserted. We were surprised how much force it took to push the tubing all the way in to the push-to-connect fittings. We initially had a couple leaks at the push-to-connect fittings, but once we removed the tubes and reinserted them all the way in we have not had any leaks.