I have been raising SMB since 1991 in an 8'deep, 1/3acre pond in NW Ohio. No problem for you in S. MN. Surface water temperatures get to 90F for short periods (a few days) during July and August. With some fairly dense weed cover or depth the fish will seek cooler areas. I believe that there are some strains of SMB that been acclimatized to tolerate a little warmer water.
