I had to replace a 4-1/2 year old Bradford White, gas-fired hot water heater (50 gal.). It was leaking. Plumber said this was due to a totally destroyed anode rod and this was due to my installation of a Culligan water softener system about 3-1/2 years ago. Plumber says that the tank had an aluminum rod and what's needed now is a magnesium rod. Culligan suggests switching out the rod or just removing the rod and plugging the opening for the rod. The latter voids the warranty, however. Plumber says BW installs aluminum rods in N. TX, not magnesium, even tho' BW's website says that they install magnesium rods in all of their models. Needless to say, I am confused about what to do. $-1/2 years on a hot water heater is totally unacceptable. We really like treated water because our water here is extremely hard. Can you help me? Thanks.