Since Wildwater Kingdom was a water park, it was only open during the day. Closing time was 7pm the last weekends it was open. I doubt that it was ever open much later. These restricted hours took away from what made SeaWorld of Ohio special, its night shows and activity.
This picture was taken at 8pm, just at dusk. You can see the lights have come on, like the park is ready to go all night. Something it was originally built to do.