I am either going to buy a new 100 gallon wide tank a used 150 gallon or a used 180 they are all about the same price, but the 180 has a lot of scratches. I am going to some kind of small stingray in there so it will have some open sand bed for it to swim about on. How much LR can I add and still have room for the ray? What are some really cool larger fish that can go with smaller fish and coral? I Have had a 24 nano for 4 years so I only realy know about the small fish lol. As the showcase fish in the tank I was going to put in one Imperator Angelfish would this be ok with the ray, coral and smaller fish. Thank you very much.