I have a relatively new Geo heat system ( < 5yrs old) which is already springing pinhole leaks in the expansion tank and showing significant corrosion at one of the valves which keeps the system filled. I am worried that at this rate the copper piping used extensively throughout the system will start to pinhole as well. The well water is pretty hard with significant iron right out of the ground but I am only using softened , hot water to fill. Is there anything else I can do? Perhaps a small ion-exchange tank on the inlet or would a sacrificial anode work if it was inline somewhere? Thanks!