UVB light is good for Diurnal animals. Those that are active during the day. This applies to most lizards, turtles, crocodilians, and a few snakes. Most snakes, including Ball Pythons are Nocturnal, meaning they are most active in the late evening and night. About the only time you should really see them out during the day is when they are getting a drink of water, or moving from one hide to the other to thermoregulate. Excessive day time activity and feeding issues are two key symptoms of stress. By providing two snug hides, and filling some the open space in the tank with some fake vines and/or plants will help reduce the stress.
The size of the water bowl is ok...