If you prefer to rim the glasses take a lime wedge and rim, then dip in salt, if you do not like a salted rim sprinkle a touch of salt in each glass, the salt really brings out the flavor.
Combine the grapefruit juice, lime juice, triple sec and ice in a blender. Pour into a large pitcher (or just keep it in the blender) and pour in the tequila, stir. (I personally just added it all to the blender- I like slushy, that is totally up to you)
it is important to use Ruby Red grapefruit juice, it is much sweeter than regular and it has the lovely pink color.