I'm not entirely certain. I had a fresh water one and it took SO MUCH work. If you go to buy the supplies for a salt water tank, the sales associate at the store could fill you in.
first off...the tank you will need will have to be at least 20 gallons...second.. these days there are lots of new filters/gadgets to make it easier on you.
i have this great book called 'saltwater aquarium handbook'