All good to know, thanks all. Even some of the anode sellers point to keeping the chemistry balanced as primary protection of components, as they refer to the LSI (Langlier Saturation Index), etc. Balanced chemistry being something TFP hammers home consistently. But can we then explain why the anode in a domestic water heater works, but not for a pool? Or do we think that's all hooey too? Manufacturers of water heaters insist on a maintained anode rod in order to ensure the warranty. Maybe they just want to sell the replacement anode rods - suggesting we replace it very 1-3 years or so? I surmise there is more to it, at least in the case of domestic water heaters. I recently replaced the one in my water heater, it had indeed "sacrificed" itself