Supporting floor for fish tank

Hello there, I am getting ready to embark on the saltwater world. I have a 90 gallon 36*24*24 tank I am going to set up as a reef tank. I will be using probably close to 90lbs of live rock. The tank will be going in a corner of a room, its not a corner tank just a plane 90 degree angle sides, but will be close to 2 corners of the room. Anyways the house was built in 1999. The tank will be on the first and only floor, there is a crawlspace underneath. The room will be basically a man cave...a 42inch TV, with a small tv stand nothing crazy heavy, a 3 seat couch, and a ottoman piece of furniture, and that's about it really. So anyways just seeing everyones opinion. My buddy does a lot of house work and did not build houses but is very familiar with basically all things house related. He said it should be fine. I just want to make sure its not going to bust thru the floor one day haha. Also...if I do decide to brace the floor the most I want to do is some cement blocks down there with some treated wood. I'm not about to jack up the house and everything else under the sun...unless I absolutely 100% have too...I estimate the weight of the tank somewhere around 1,300-1,500 lbs. Thanks for the comments.