rodi automatic shut off

[pirate]

As I study the picture I had the previous one hooked up that way and no luck either, at least it looked that way without the pressure tank. |I had the most amount of luck when I had the shut off hooked up to the waste line,I had it pulsing but that was it. But if i don't have the water pressure to shutoff the solonide where can I buy just a plain shut off valve like the one pictured?