RO/DI Help!!!

[oilfieldsafety]

I have a 6 stage "Reef Safe" RO/DI system that recently developed a problem that I haven't been able to solve. When the system has filled the resevoir and the shut off shuts the feed off, the resevoir tank leaks back through the system until it trips the feed water back on. I have changed the shut off valve with a new one from BRS but still have the problem. Any and all feedback appreciated.