CK14 when I first started out doing bass tourney's I used a big cooler with an aerater on it and it worked great. Never had a fish die on me and I used it during the dead of summer in Missouri. Just make sure you have a lot of spare DD batteries, or I recommend buying a 12V pump that runs off of a car battery. Also, after each trip make sure you clean the cooler with baking soda. Also, that blue stuff that you can add in to the water to make it better for the fish wouldn't hurt either.
"If people concentrated on the really important things in life, there'd be a shortage of fishing poles."
Dave