There may be several reasons for this:

1. The fan may not be working properly. Open the spin cover and see if the fan can turn on.
2. The humidity setpoint for your theme might be too high; considering lowering your humidity setpoint.

The humidity setpoint for your theme might be too high; considering lowering your humidity setpoint.

Also, we find that if the fan is always on, the tank rarely fogs up. To do this:

1. Go to Commands
2. Change the Fan Mode to “ALWAYS ON”