Salt Spray Corrosion Chamber

Hi, I am doing a project where I need to build a salt spray corrosion chamber, following the standards in ASTM B117. I was thinking of using a fish tank of some sort for the bulk of the chamber, but the roof needs to be sloped, so it needs to be modified. How do you design something to have an airtight/watertight seal but can still be opened and closed for access to the inside of the chamber?