Mark, We were just out in your neck of the woods doing pond evaluations for a local real estate company and we also checked on some customers.
oxygen levels were quite good for this time of year but now is a tough time to act it is a little late in the season. Let mother nature take it's course and plan for next year. Most of the ice is stratified in 2 foot depth and hard for sunlight to pass through if you have 8 foot depth i would not worry. If heavy tanin is present you might loose a few.
Scott
