Hey bro, unfortunately as I may be moving out of SG in the 3rd quarter this year, I am unable to complete this project.
However one thing to take note is to check if your condo does have an underground carpark directly below your unit.
I would think overall weight of the tank is not as significant. Other bros have done similar sizes to what you are planning with no problems, even without staying in a ground floor unit, and I hope it works out this way for you!