You can change the anode rod to another type, or remove it. Removing it voids the warranty. Adding bleach/chlorine will not be a permanent fix, bacteria are the cause of the odor and they live in the water and the odor will return shortly after the chlorine is gone. The bacteria is harmless and is usually IRB or SRB; iron and sulfate reducing types.
The other choice is to increase the temp to 140f, that kills the bacteria, including Legionella if it is in your water. It is dangerous.
The manganese greensand filter is not going to help at all unless there is an odor in the cold water. The sediment filter will only remove invisible 'dirt' that all waters contain and there is no point if removing it. Especially if you are using a disposable cartridge type. Save your money and remove the cartridge.
Quality Water Associates