I had a 180 with concrete slab floors. More importantly you need to get your apt permission. If you stick one in there, and something does happen you are up poo creek. Read your lease! See what that says about tanks. Get written permission, if possible get them to talk to the builder. And be sure you set your tank over the floor bracing. In my case my tank started leaking, I caught it in time, but if I hadn't, I'd been liable for 100,000 in damages.