Large tanks and tile floors

[lastlight]

My 225 is on the main floor which is tiled. I haven't had it filled long-term but I don't expect to have any issues. My floor is very re-enforced to avoid sagging which I think would definitely lead to cracked tiles. A concrete floor should be gold. My tiles however are ceramic and have no irregularities which helps.

[fkshiu]

A flat and true base for the tile and you'll be fine. If it is a new house with relatively young concrete, you should install an isolation membrane like Schluter Kerdi to prevent shifting as the concrete ages. Use porcelain tiles which are about as hard and strong as you can get.