Basement reinfocement

[Gripenfelter]

I have 2" thick ply wood floors with thinset, steel mesh, more thinset, and then marble/porcelain tile on top. 300 gallon fish tank with stand will weigh 4000 lbs.

Under the floor are 2 I beam joists 16" apart from centre or 12" apart from edge to edge supporting the 7 ft tank length wise. I boxed in the I-beams and put 4 steel teleposts under the joists. One side of the joist rests on a concrete exterior wall. The tank is 12" from the exterior wall. The joists are 16' long and the other side sits on a steel beam.

So far with 1500 lbs or so on top of the joists right now there is 0 degrees of deflection and that is without the teleposts installed. I would be surprised if I saw 1 degree of deflection.