Replacing anode rod
Now that our "6-year" gas water heater is approaching 12 years of age, it's probably time to change the anode rod! (hopefully, not too late). When I looked online for directions, there were a few discrepancies, so I have a few questions. Some said to turn off the gas, others didn't mention that. Neither does the instruction manual that came with the water heater. Can I just turn it way down so it doesn't fire up while I work on it? If I do have to turn it off (there is a valve-cock at the heater, so I'm just talking about the supply to the water heater, not the main gas supply to the house),I'm not sure if it would be o.k. to turn it back on by myself (and light the pilot). Or should the gas company come and do that?
I assume, based on my research, that I just need to drain some of the water, not all of it. Right? how much is enough (it's a 40-gal heater)?
Finally - any tips for loosening what is sure to be a super-stuck hex? Will I need a heavy-duty ratchet, or just a big head for my regular one?