Kevin:
I have many juvenile nurse sharks from time to time. I can tell you that mine grow at a rate of about 9-13 inches per year. When a nurse shark is full grown or even half its full growth it will need a long and wide tank to live in. I am talking at least 12'x15' They are not like other large sharks that really only need about a 4 or 5 foot wide thank. However those sharks also need tanks like 15 to 30 feet long. So either way you are talking about some seriously large tanks for them.
Jim