Water Heaters - Anode removal

We recently moved into a rural home with well water. After coming into the house, the water goes through a whole house filter into a water softener and then into the hot water heater. The hot water reeks of sulphur so my plan was to take the anode out to see if that would stop the smell. The problem is that for the life of me I cannot loosen that anode bolt. I've had three people helping and we can't loosen it. The heater is only a year old, but there has been a good amount of water in the basement when we first moved in causing some rust. The basement has since been dried out, but I can't believe the bolt is rusted on there. Do they use impact wrenches to install those bolts? Or am I just a weakling? Any tips?

You are not the first to experience this. One poster said he put a 4' pipe onto the wrench and still couldn't move it. Impact wrench seems the sucessful way to do it. Good luck.