Here is a similar question: I have a newly installed 50 gal AO Smith Vertex condensing gas heater which I am feeding with softened water. After being away for a few weeks, I found that a lot of gas (presumably hydrogen) had accumulated in the system. I read that softened water can consume the anode (single magnesium) rather fast, and a powered anode is recommended. However, this site specifically excludes Vertexes from those suitable for powered anodes on the grounds that the internal configuration is too complicated. Does this just apply to the Ceranode extendable product, or is there a problem with using the Corro-Protec one, even though it is much shorter? I note that AO Smith does produce a powered anode for its larger commercial condensing models, but has nothing for the Vertex.