Fyfer - Tell us or give us a PBoss forum link to more about some of the details of your pond. I need to know how old it is, maximum depth, water clarity, if pond dye is used and amount of dying weed growth going into late fall. Also helpful is amount of dead tree leaves that were added to the pond this fall. Water clarity of the open water is important to know. We need to estimate the biochemical oxygen demand of your pond during winter to determine the need for winter aeration. All this info provides for a good, educated, remote evaluation of how much if any that you need to be winter aerating your pond. You said "According to our pond manager, the goal is to leave an open area for gas exchange....". This is basically true for shallow, older eutrophic ponds with years of organic muck buildup. Depending on the in-depth aquatic ecological education experience and understanding of your pond manager he/she may be just giving you very generalized winter, aeration, vendor directions rather than the specific winter aeration / oxygenation needs of your pond.