Might have to change to a water meter real soon ( no choice) and currently use a merlin RO. 300ish ppm down to 20ppm so happy with that at the moment, but it wastes loads of water. What is everbodys opinion on the most efficient RO inc waste water? Or any other suggestions like using a booster pump, catching waste water etc. I need aorund 1200 l of pure water a week but this may be going to get more in the next year or so.