pigman1 wrote:
It's sort of hard to tell if the light ring you can see in the pic is, sediment or part of the old anode. I'd take a small flat blade screwdriver and see if I can tap the stuff loose. If it shatters, it's scale and the center rod on your nut is just stuck in the same scale. After you get it out, you might have to go in the hole with a long drill rod to brake up scale. Crunch it up, flush, crunch it up, flush...till it's as clean as you can make it. With that much scale and corrosion, you have probably got a few weak spots in the tank. I'd just keep it in mind that you might need a new water heater tank soon.
/\ This. Break loose all that you can, be careful of the threads on the fitting while doing this, don't damage them, and flush out all that you can. You might be able to mix some "lime away" with some water and fill up the lower portion of water heater with that and let it do it's magic. That water heater won't last forever, with that kind of abuse, and lack of maintenance.