MN,circulating 33 degreeF water under the ice is better than aerating open water with the air temps in the single digits.I do not know what system you have but again thawing 4-6 inches of ice with low a cfm pump is easy to do.I see more midwest and northern ponds "over circulated " than I do "under aerated" in the winter months.Keep an eye on things and you should be fine.
