Large Fountain Clear will prevent organic contaminants from forming (such as crusty white scale deposits, iron, copper and hard water stains). There are two technologies involved in this product. One is that which I first mentioned, and the other is a bio-enzymatic activity to keep water clear and free from the organic debris that can make water cloudy (bird droppings, i.e.). It is recommended to start with a clean surface, perhaps using ML/Soy Based Bird Bath and Statuary Cleaner before refilling the fountain. Rinse and repeat, if necessary. Then, in the established fountain, use Large Fountain Clear weekly to maintain it. Do partial water changes as needed, which will be far less often than without using this product.