How much experiance do you have with salt water? If you are just starting give yourself some time on this tank and start with some study time. Figure out what you want to do with the tank. What you want in it and what will work for what you have or can spend.
Just to take things and through them together just because it works in one place does not mean it will work for you. Understand what you need so things can go smoother and you can have more enjoyment.
Is this going to be a coral tank, non coral tank, just fish, and many other things to choose from. Then you can understand what is needed for your bio-system to function properly. Altitude, placement, accessories, lighting, temp. fluctuations, etc. etc.
Any one can give you a number to go with for what you ask, but is this what you really need?