Jeff,
Aerators are mostly for summer use unless your pond is very shallow in the winter, or if you have heavy weeds in winter which consume O2, or unless you can't get the snow off the ice. If it is by your house you may be able to keep the snow cleared? Warm winters in MI can present a problem where the ice is too soft to walk on and the snow can build up for many weeks keeping sunlight out of the pond in the winter.
Also, I learned myself that it is very important to know the exact depth of your pond. I assumed based on what I had it excavated to that it was that depth. But get in a boat with a weighted string and measure exactly. 13 foot should be good to help with preventing winter kill. But if water goes down in the summer and stays down in the fall your depth may change.
Do you have pictures of the site, or the dig, or what the soil types are? I'm curious if yours is a groundwater pond or if you have a means to fill it or top it off if you need to? Do you expect to have much loss through the bottom or sides of the pond?
Will you have mature trees around the pond dropping leaves in?
Do you have a source for crayfish locally?
