IMO you should have never of left the first place and the reason for your move was extremely irresponsible. If you are going to live on your own and need to support yourself I am sorry but moving because you can have fish tanks was not a smart move at all and your lucky the old land lord is considering you because that looks bad on your rental history and that is not something anybody wants. You do not need a 125 or anything else right now. You take what you have if you have a 75 gal tank then you need to deal with that tank and those fish ONLY and stop worrying about larger tanks and other tanks. I live with in my means... I am not going to go buy something if I cant afford even if I really want it. You need to learn that bills must be paid and you need HEALTHY food and that comes before any luxury including fish or new tanks, cable, internet, etc. You need to learn how to be a responsible adult if you plan to make it on your own.