I have the same thing on my RO unit, to my storage tank, Cliff. That being said, I also turn it off manually - 'cause it HAS failed TWICE. In addition, I've heard so many horror stories about RO units and top offs running amuck, that this way, the MOST I can dilute my system is 40 gallons - probably not enough to kill everything off. I LIKE redundancy. I also purchased 5 water alarms off of ebay for about $10 each - and use them all over the place. As long as I'm home (that's been an issue lately...), they will also let me know if a problem comes up.