But a bathtub is supposed to be re-enforced with an extra or two 2x10 joists under the floor. The same with a toilet or anything else heavy and stationary in a house.

I know my floor creaks, snaps, and groans for some time after someone's had a bath. The house is new and I'm not worried about it but it goes to show that the forces involved are having an effect.

Like I said earlier though my guess is that it's OK. But for the love of goodness don't listen to ME because I tend to learn everything the hard way through the school of hard knocks. I always heard the addage that 75 gallons was a pretty good threshold for a tank on an upper floor. Not sure what it was based on. But the premiss was that 75g and under was never an issue, anything above 75g should have a little forethought put into it (ie., not necessarily "don't do it" but at the same time, do consider the variables). Having said that, I've never heard of a tank causing a floor to catastrophically fail and contents of said floor relocated to the basement in a free fall sort of way. More likely though water spilling can drip through and cause different sorts of problems (mold in carpet underlay or in walls, or hardwood swelling, etc.).

Thank you
 

Thank you so much to all of you for all your help I didn't expect so many to answer my little question so again I really appreciate all your help. I will let you all know with pictures if all turns out well. Right now I just have a 33gal LR and Fish tank its pretty but I want my big tank set up in salt:)

Jenn

The terminology is live load vs dead load, if you weren't sure :)

But you are correct, the difference between load types is exponential.

I have 155 main + 33 sum on my main floor. It is perpendicular to the joists and near the outside wall. I did not see any problems for couple months but then i got a contractor to do Joist Sistering to be safe. I probably going to build a support beam underneath once i figure out what i want to do with my basement. Be safe than sorry :-)

I have a 150g tank with 70g sump in a Mobile Home. No extra bracing, no issues. If you put tank across the joist's, and close to a load bearing wall, you will have no issues either.

One more thing i forgot to add is that my contractor told me my joint bent a little when he measure it with his level.

ive got my 125gal against an ouside wall with 2X10 joists 16" apart. It sagged the floor a bit. Im not worried about it as we get used to get alot of snow here which is an immense amount of weight and we dont get close to that anymore. Im doing a 250 gal in my living room perpendicular to the joists and against a load bearing wall and will be putting in a support for that one. Saying that though my 46 gal in my kitchen moves more then i care to like. If im sitting in front of my tank and my dogs run by i feel the floor move. Thats up against a load bearing wall too. Id personally at least ask an engineer as they prob dont need to see your house, just know the construction, floor joist size and spacing and weight of the tank and footprint. That should give them an idea. I just dont think id like 1500lbs crashing down on me at 2 am. Just my 2 cents.

130 gallons is a lot heavier than the average person.
I beg to differ on this statement 130g tank weighs about 1300 pounds when not in motion when you walk by it it goes into motion. As far as being OK to have on main floor I would only put it where a bath tub would be or in a alcove as those areas are made to hold extra weight also the main supporting wall that runs the length of the house is mad to support extra weight. if you have the tank perpendicular to the floor joists they will hold more weights you are distributing the weight over more floor joists a 6 foot tank is over at least 4 floor joists. I would phone a engineering firm and ask to talk to someone about the situation you have. now if you can have the tank perpendicular to the joist and on top of where a wall is down stairs it would be OK then I would think.Or put it where the utility room is and have telescoping posts put in below the tank that should be goodI would think, but I am not a structural engineer.

Bill

floor joist spacing is the same under my tub as every where else.