Marty - we have a Koenders (windmill, not electric) aerator on a 3-acre pond, one on a 7-acre pond, and three on a 20-acre pond. We ice fish, and the kids skate and play, on the ponds given South Dakota winters. Obviously, stay away from the open holes, and in a warm year like this, we're always VERY careful about checking before we venture onto the ice.
Hope this helps a little.
Dave Willis
