What he said.

You can buy clear cases for model kits. Hobby Lobby has them. I bought one for my 1/700 scale Mogami waterline kit. Worth every penny of it. I don't like the idea of dusting off a 1/700 scale waterline ship model without the worry of breaking off the main mast or worse.

I'd definitely would check out your local Hobby Lobby or Michaels. You might be able to screw down your tank kit from the bottom so it won't shift should you need to move the case.