In my last apartment I had two 125g with no problem, just was made clear that I was liable for any water damage (there was none). Really, if it is an apartment, you just need one that allows pets. Then just check the lease that they can't just enter your apartment whenever they want. With that you can just move the tank in after signing the lease, and then move it out before they do their last walk through when you move out. The only problem you would possible run into is if you ask them to come in and fix something.
As long as you don't welcome them into your apartment to fix something (or any other reason) then they cannot enter. My brother had a similar situation where his landlady entered his and his wife's apartment when they had not asked her to do anything. Supposedly it was against the lease to have any candles. She ended up losing out when it wasn't in the lease and was found in violation for entering. End result: my brother and sister-in-law got 6 months of rent free!!