Fresh Sour Mix?

[foodnfoto]

As the weather warms, I start yearning for tasty thirst quenchers that always seem best when I'm all sweaty and covered with dirt and mulch from the garden. At the end of those sunny days when it feels as though I can't lift my arms anymore I can always find the energy to lift a nice cold margarita to my mouth if nothing else.
I used to have a recipe for delicious sour mix that when added to some triple sec and tequila makes a wonderful margarita. It used fresh squeezed lime lemon and orange juice, sugar and an egg white.
Unfortunately, I seem to have lost the recipe.

Are there any bartenders out there who know of a dynamite sour mix that I can whip up in my kitchen?

BTW, those acid green concoctions sold in bottles or dry mixes (mr & mrs t's) always have an off taste-kind of metallic and chemically.

My dry, dusty throat is yearning for that fresh taste-Please help me.