I have noticed massive media evaporation (>50% volume) from culture dishes after 72-96hr inside a Memmert ICO50 hypoxic incubator (Temp: 37C, humidity: 86%, CO2: 5%, O2: 1%). I've confirmed the temperature and humidity indicators are accurate. Evaporation is only a problem with culture dishes and not capped filter flasks. I think the issue stems from the wall-mounted fan (rather than ceiling-mounted) causing increased air flow through the dishes. The speed of the fan cannot be controlled. I've tried placing the dishes on aluminum foil to avoid up-draft coming through perforations in the shelf, which seemed to improve but not solve the problem. The dishes cannot be parafilmed as they need to equilibrate with the hypoxic air. Any suggestions?