Our house was built in '92, and we purchased it in '00, I'm assuming with the original gas fired water heater. Our town had very hard water at the time (19) and the water softener was not working at time of purchase. After replacing the softener and using Potassium (in lieu of Sodium) pellets, we have "lost" 3 water heaters in the past 7 years.
The 1st was a couple of years after the new softener was installed, and about a month after switching water suppliers to a "softer" water (9). It's demise was attributed to the hard water and previous non-working softner (previous owners never replentished the salt). The 2nd, was within a year of the 1st and was attributed to a "bad" unit. Our third went this morning, about 3 years after the 2nd was replaced.
My question is about the salt. Could using the Potassium cause the heaters to "rot" quicker? The last two have "blown" at the top, not the bottom. I drain 20+/- gallons off the bottom every 6 months, and I reset the softener when the water supplier was changed, though I did make it a bit soft (4 or 5, I don't recall). My neighbors have their original heaters, and are using Sodium pellets in their softeners. The houses were built by the same builder at about the same time and I'm assuming by the same plumber (who still works for them).
The only difference is the Potassium that I can see.
Any ideas/help would be appreciated.