So, I was contemplating life, fate and the galvanic table this morning and I had a bit of an epiphany. The pipes exiting the tanks are galvanized transitioning to PEX through a brass valve and brass PEX couplings. About a year ago I noticed that the brass valve was dripping and, after removing the insulation, I noticed the galvanized pipe connected to the badly ageing tank was rusted out and leaking. The aluminium anode on this tank might have already failed by then. The galvanized pipe on the other tank was rusty but not nearly as bad. At the time I just replaced the bad parts and put it back like it was originally to fix it quick. My thought is that the brass valve will rust the steel pipe and the tank (just a little), the steel pipe and tank will rust the aluminium anode, and the aluminium anode will rust the zinc coating on the galvanized pipe. The galvanized pipe will become the tanks sacrificial anode, sort of. The epiphany is that the zinc galvanize coating will rust a magnesium anode, so any water heater connected to a galvanized pipe should have a magnesium anode to help keep the galvanized pipe coating from deteriorating and to help prevent brass from deteriorating steel. Does this make sense?
Yeah, I know. Quit using galvanized pipe 😕