Personally I would save the windmill $$ and add to solar fund. I am not sure which windmill you are looking at, but either one of mine would have paid for a "direct drive" solar rig.
There are some affordable solar aeration rigs out there. You don't need battery backup, just direct driven solar powered. It will only run while the sun is shining. There was a member of this forum that lives up North that was building them. You could probably find him with a search.
