Do I need venting to outside for this new Tank build?

[The Codfather]

I recommend that you do, I hooked up my fan to a honeywell dehumidification switch. This automatically turned the fan on when it reached a preset value. I have central air in the house so humidity is not an issue in the summer/early fall, but it can be a problem in the winter months. I would seriously consider this option, as it is easier to do it now, planned ahead, than later on down the road. Just my opinion, HTH,
Bob