Back filling fresh water tank .....again

[RodeWorthy]

I have about had it with problem of my fresh water tank filling when connected to fresh water supply. This is due to internal check valve in the pump leaking or blocked open with debris. The current problem is sporadic but a nuisance just the same. This forum has reported many incidents of this problem over the years.
I am going to install an external check valve in the inlet line. This is not a new solution -- someone else posted this solution in the last year or so. A search did not bring up the information which I believe gave a part number for a valve that could be purchased from Lowes or similar store.

Anyone know anything about this solution? Would like to hear from you if you do.

Thanks,