RO purifiers that drop from over a litre a minute to half within a year, with a buzzing pump and ever more frequent starts and stops, are usually blamed on the filters. The real cause is often an eroded impeller, air ingress at the pump head, or a low-pressure cut-out that trips at the wrong point. The NL-ROP-6 separates flow, pressure, suction and dry-run protection on six stations.
