225 degrees is about right - when grilling ribs you want to make sure you use indirect heat, meaning that the ribs are not directly over the flame, but instead a shallow pan of water or something else, that is the secret to keeping them from drying out :)

Here are some more tips on grilling baby back ribs here you might find useful, along with step by step directions for getting your grill perfectly set up:

Grilling Baby Back Ribs

Hope they are tasty!