Are we looking at multiple floors here ?
I can't tell as it looks like an elevator shaft
Are pictures 1 and 2 basically the same location ?
If so, what's the measurement from the wall to the inside edge of the left/right beam ?
I ask as it looks a bit close to the wall to support any deflection
If it were me, I'd add another full beam left/right directly under the front of the tank, and have it supported on new posts
Make sense ?
If the pics are showing 3 floors, then you'll need posts going all the way to the first floor to support a new beam for the front of the tank
I have never liked seeing my tank do a 'wave' because I have company over