well i have a bottle of gatorade in front of me:
water, high fructose corn syrup, sucrose syrup, citric acid, natural flavor, salt, sodium citrate, monopotassium phosphate, modified food starch, glycerol ester of rosin, yellow 5.
well, it will increase the salt (salinity) of the tank slightly, increase your ph, add some preservatives, and a bunch of sugar.
IMHO, few water changes and you will be fine. but if you said that there was just alittle bit. i wouldnt bother doing anything besides the 50% water change you already did.
-chris