Hello fellow reefers i have a serious question

[lastlight]

My fishroom had a bathroom fan on a humidistat and a seperate fresh air intake to feed the room. I had the room set to 40% humidity. My tank wasn't running very long and after tear down I did find mold on a wall where some containers/boxes were either touching the wall or very close to it. Perhaps my fresh air vent and the fan were too close together and I wasn't getting great airflow. Perhaps this solution no matter how well setup isn't enough I can't say for sure.