There are a lot of factors that contribute to rust including the pH, dissolved oxygen and to a lesser extent other oxidizers (including chlorine), conductivity (salt), temperature, and others. However, in pool water it appears that pH is the most important factor and that maintaining a pH above 7.0 makes corrosion much less likely. The saturation of calcium carbonate that is done in plaster/gunite pools also forms a thin protective layer on metal surfaces that inhibits corrosion.
So I would say that keeping your pool water balanced will likely not corrode pool surfaces that are in constant contact with your pool water, including your heater elements. On the other hand, splash out onto deck or other surfaces that are exposed to air is another matter and in that environment a salt pool splashing out salty water may corrode metal faster.
Hope that helps. It would be interesting to hear people's experiences with AG pools. I suspect that with stainless steel, there isn't much of a problem. It would only be with basic steel (iron) where they might be some issues.
Richard
Bookmarks