Do I need to reinforce the floor?

[wolf_bluejay]

Originally Posted by Gripenfelter

7 foot 200 gallon tank with stand will weigh about 2500 lbs.

It will sit length wise on 2 floor joists that are 16" apart.

The tank will sit perpendicular to an exterior wall.

Joists are wooden I-beams and sitting in the concrete wall on one side and the other side is sitting on a steel beam.

Joists are 15 feet long between the concrete wall and steel I beam.

Do I need to reinforce the floor or will I be ok?

House built in 2009.

Just looking at the numbers, and I'm somewhat guessing because you don't specify the height of the wood I-beams.
This is a bad, very bad idea without reinforcement.
I doubt the floor would fail, but the flex in the floor from the weight would probably cause the tank to break. A 15' span is pretty big, and with a 7' tank you are going right to the middle of it. And to give you an idea, if you have a "larger" friend, say 300' or so, get him to stand where the corner of the tank would go, and put a glass of water on the floor nearby. And now stand back and get him to jump up and down. Not hard, just bounce repeatedly. You will see the "flex" in the floor.

As well, a 200 gal will weigh in much more than 2500 lbs and closer to 4000 lbs with sump, glass, rock stand and other equipment.
For comparison -- my 220 gal is perpendicular to my joists, with the back side of the 6' tank resting directly above a concrete wall. The joist span if only 8.5'.
I added a closet below the tank on one side, so the span is really only 6' and I added extra joists so that the tank was on 7 instead of 2. I glued and screwed the extra joists to the existing, and beefed up the main beams they rested on. The tank is not on a regular stand, but rather a 3' "wall" build with larger lumber.
I really overbuilt the support, but it cost me a total of $100 to sleep at night. and even after all this, the floor deflected still by about 1/32" when the tank was filled.

So, do you want a tank that moves, shakes and slops all over the place when someone walks past it. Or do you want a tank that doesn't scare the crap out of the kids if you jump on the floor in the room?

Honestly, support the tank. I had a 90 gal before my 220, and it moved a bit as you bounced on the floor while working on it. With the new one, I could have a party beside the tank and feel comfortable.

Just build a closet at the around the tank below (you might have to do a little concrete work as well).