From "http://www.cichlid-forum.com/article...ium_weight.php "
Myth #5: "If the floor in my kitchen can support the 500 lb refrigerator then the floor in my living room should be able to support my 500 lb aquarium." This isn't necessarily good logic. Do the floor joists span exactly the same distance in both rooms? Do the other items in the rest of both rooms have the same weight? Is your refrigerator and aquarium the same shape so that this same weight is distributed over the same number of floor joists?
The reason that there is rather large safety factor built into the floor design is to take care of as many unknowns and imperfections as possible. Did the plumber cut a notch in the bottom of your floor joists for his piping? Is there any insect damage or maybe a little dry rot? Is there a split or knot in the wood in a zone of high stress? No one wants to have to replace their floor because it is not in perfect condition. So if your aquarium loads your floor over the safe load limit you might not be in danger of collapsing the floor, you might just have less safety factor than recommended. If you're stretching the load limits of your floor structure, then be absolutely sure that your floor structure has no imperfections.
Myth #5: "If the floor in my kitchen can support the 500 lb refrigerator then the floor in my living room should be able to support my 500 lb aquarium." This isn't necessarily good logic. Do the floor joists span exactly the same distance in both rooms? Do the other items in the rest of both rooms have the same weight? Is your refrigerator and aquarium the same shape so that this same weight is distributed over the same number of floor joists?
The reason that there is rather large safety factor built into the floor design is to take care of as many unknowns and imperfections as possible. Did the plumber cut a notch in the bottom of your floor joists for his piping? Is there any insect damage or maybe a little dry rot? Is there a split or knot in the wood in a zone of high stress? No one wants to have to replace their floor because it is not in perfect condition. So if your aquarium loads your floor over the safe load limit you might not be in danger of collapsing the floor, you might just have less safety factor than recommended. If you're stretching the load limits of your floor structure, then be absolutely sure that your floor structure has no imperfections.