sport drink

I want to mix my own sport drink. Looking at the ingredients
of Gatorade, it's not too appetizing.

I'm thinking, half water, half orange juice. Then, salt, but how
many teaspoons, or grams, per liter? It should match the
body's salinity.

Also potassium, to replenish what's lost in perspiration.
That's why long distance runners eat bananas, I believe.
Can you get potassium in powder form, and what dosage
in the drink?

Other minerals?

--
Rich