This nutrient is the cheapest and is often the one that is overlooked when evaluating a feeding program. The amount of water needed for billies will vary throughout the year. The water needs to be clean and always available. The containers need to be cleaned at least once per week during the winter months and more often during the warm months. This will reduce the amount of algae present in the container. A small amount of disinfectant can be used to clean the containers.