First off, yes, a powered anode will solve the odor issue. But the trouble is that you have a Buderus. It may not be possible to find a powered anode that will work with it. The user guide appears to show a hex anode, but the thread size may be wrong because Buderus is a European design and the anodes are not the same as American ones. If it’s compatible, though, you’d want a Corro-Protec, SKU23. Check with Buderus to see if the thread size is compatible but don’t tell them you’re considering a powered anode. That might void the warranty. And that’s not because there is anything wrong with powered anodes. Manufacturers only warranty products they’ve tested, which is actually sensible.