Blue is the stock passport. These days you are not always required to have a different one for a tour. In fact, I think the SOP now is for you to have a blue one except for special circumstances.
A Green passport is a Special Passport. It identifies the bearer as an official of the Government of Canada, but without Vienna protections.
A Red (or Maroon) passport is a Diplomatic passport, giving the bearer certain Vienna protections.
CF members only get a red passport if on a diplomatic post: Attache, or other diplomatic position that requires diplomatic protections under the Vienna Conventions. A green passport provides limited status as a government official. A blue passport is what everyone else can get, and is usually all that is required for troops on tour (despite the use of green passports in the past).
Normally one is allowed to carry only one passport at a time, so if you have a blue, and need a red or green, the blue will be taken away.
Acorn