This will be fine on a second story of anything resembling modern construction!
Assuming you’re not living in a Victorian, I wouldn’t worry about 40-50gal of water weight (~8.5lbs/gal for salt water, and aquariums are typically measured by outside dimension volume; so subtract ~10% for actual tank volume)
Here’s a great stick on floor support, definitely worth a look through if you’re getting into much larger tanks not placed on a concrete pad!
Do I Need Floor Supporting?!? I always ran across differing opinions on floor support when it comes to our hobby. This was written by a structural engineer, but in what I feel, easy to understand language. Thought maybe someone might be interested... "By: Kevin Bauman One of the questions...
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