What part of Wisconsin are you in? Temperature range of ambient air and likely temperature range of water in pond, as well as how brutal and how long your winter conditions are determines how necessary aeration, pond dye, and 'chemicals' might be in a 1/10th acre pond.

Is there wind across the water much of the time or is it sheltered?

how did you determine depth of deepest spot? Actual measurement to muck layer using weighted line? It may be worth double checking depth as it will save you on your purchase of aeration equipment when the time comes and there is a big difference in dissolved oxygen in a true 20 foot hole in a northern pond compared to a measured depth of say 10-12' in the 'hole'.

Is there natural inflow of water, spring, groundwater, or runoff changing the water levels over the seasons?