Ron: "There is a buffer of pipe between each tank valve. If there was any backwash contamination, it would be trapped in the pipe between tank valves."
This has me baffled, are you saying there is actually a check valve between the two tanks? Ron with all your great connections at PC maybe you could get an actual diagram on the plumbing manifold to the tanks? Or maybe you could post a simple sketch?
fandj, thanks for that link. I have never been exposed to this product. The vids are worth watching. I'm not sure why hepvo is not standard equipment.
Doug