Basement reinfocement

[Coleus]

Ok i need all your expertise helps here, I need to put a 135 gallon tank (120''x20''x13'') between two floor joints. there are no support beam anywhere near them except for the concrete wall, which is 1.8 feet away from the tank and is perpendicular to the two joints.

So, putting an underneath beam that is perpendicular to two joints is not possible. Putting a beam between 2 joints and parallels to them also not possible because of the floor plan.

My question is : If i put a support beam that is diagonal between 4 joints (the tank is in middle of these 4 joints). Will that works or is it useless? Or sistering floor joints is good enough?

Thanks