My basement fishroom did not cause a problem for me until I had over 1000g down there (lidded tanks).
I don't think your SO would appreciate people walking in your home and knowing right away that there is a big tank in the basement because it smells like a fishstore/petstore.
I installeda dehumidifier that I have draining to a pump that pumps the waste water directly into my sewer main. It runs maybe once a day (this is with 60+ tanks running) so you may not have that much of an issue.
Thing is, you don't WANT an issue. It wouldn't hurt to invest $100 or so in a small dehumidifier to have out of the way that would prevent issues. I would much rather empty a dehumidifier every few days then figure out what to do about black mold from too much moisture. It can be a serious health risk and is easier to prevent than to treat. Worst case scenario for planning for it is you have one more task each week to empty it and a slight raise in electric bill. The other (maybe a benefit?) thing with dehumidifiers is they add a significant degree of warmth so in teh winter months, can help your tank heaters not have to run as hard.
Otherwise, I would make sure you have a plan for your water drain and fill. That is a lot of volume and if you don't have a sink down there, you will regret it even if its just for maintenance of your filtration media and not necessarily your drain and fill.