Advice? Flooring question

depends on several factors, hard to tell without alot of particulars and each situation is different.

how wide are the joists?
spacing of joists?
against a load bearing wall on a cement/or block foundation wall?
subfloor thickness, finish flooring thickness (if finished wood ect)
stand type? full base or hd feet?
perpendicular or parallel to the joists?
and other factors im not thinking of atm too.

tank water rock etc is alot of weight. look on the bigger forums and there are tons of threads on that topic. i wouldnt go over 90 on a non reinforced non slab floor just to be on the safe side, but depending on construction that could be too much as there is alot to consider, others may disagree and say bigger but ive had a 75 sag a floor a bit running perpendicular over a few joists 10"ea, not terrible but its noticeable now (house built 1954). all mine go on a garage slab concrete now. if you have a basement thats fun/habitable then id consider down there and you can have as big as you can get down the stairwell. otherwise just get some post jacks and some lumber and beef up the joists and support to be safe and have peace of mind

 

and be safe and go concrete slab in your basement if your questioning upstairs placement. be safe. each house is different so what works for one person could be a disaster for another. i reinforced my floors for my old 100 gal over our crawl space after the 75 issue in another spot in the house and the 100 was fine w 40 sump and rock ect.

ps im no structural engineer so do your research lol or put a big ol tank in the basement and not worry haha

 

ya you will be good.