Yeah, they have been in the system for a while and near the end of last year a lot of PH down into the tank and the PH was 2 for a couple of hours. After that, they were never the same. I have been looking for stainless steel alternatives as they will last forever. I will try it out on a couple of valves and see if they act differently to the others, in my system.
Nice tip. My only regret is that I have only one like to give 