Sounds like your "holding tank" is probably your pressure tank, and wouldn't be aerated. Generally, well systems go from well, to pressure tank to house supply. A holding tank supplied system generally goes from well to a poly holding tank, which by default is aerated, then a second pump moves water from the holding tank to the pressure tank. I don't know if this would help in your case, but works in mine. Sounds like removing the anode would be the easiest first step according the guys here that have obviously run this rodeo a time or two.
