I just replaced all this 45 year old setup on a filter with ball valves and PEX. The old gate valves were so eroded that you could not shut the water off all the way and the galvanized pipe was developing leaks. Don't have a photo of the new valves and all. I love PEX. Invariably I have leaks on pipe thread joints. For whatever reason I have to keep tightening till I break a fitting or something. Teflon tape and pipe dope don't give me different results. Glad I never had to make a living as a plumber.
