I have a vyair 200gpd ro which I've had now for 3 years. Haven't needed to use it since May 2014. Nearly 18 months. This was due to harvesting rain water and getting some off a friend I know. Bought some filters for it about a year ago & today decided to change them. Put them in. Connected it up. No flushing. Ran it for about a minute & water was entering at 275ppm & coming out at 11ppm. That's a good RO.