At Volcano Bay, there is an Icee Station just across from the exit of the green and blue trapdoor slides (can't remember their names). Flavors include Blue Raspberry, Wild Cherry, and Coca Cola. It is not self-serve, but you can get refills. Line moved pretty quickly on a very busy Memorial Day. The TM working there said there is another place inside of Whakawaiwai eats where you can get refills, but I never made it over there.