2573 – 1″ Brass Aerated Bubbler Nozzle. This level dependent nozzle has its air intakes below the surface of the water. If the water level drops, the cascade will produce a taller, thinner pattern. Thus to maintain a consistent effect, the water level must remain constant. This is typically accomplished by using an autofill unit in the fountain pool with a dedicated water line and an overflow. Level dependent fountain nozzles also require more pump horsepower as well as higher light wattage than similarly sized level independent fountain nozzles. The water stream has a white frothy look and is more wind-resistant. Level dependent nozzles include cascades, bubblers, geysers and most types of aerator nozzles.