120 gallons + sump?
Say it's 120 gallons*8.35. That's about 1002 lbs in water + glass (maybe 250 and studs, say 300). That's 1300 lbs that you will have to share on that floor.
1300/(3x4)=108.33 psf. That exceeds your typical 40 PSF. At that point, you have to take a look at span, the spacing...