The Stainless Steel Series UVs are ideal for ponds, aquariums, and water features. These units are constructed of 316 Stainless Steel electro polished and passivated. Stainless steel units have features that allow for quick installation and easy maintenance. Aqua Ultraviolets UVs will clear your water in 3-5 days, sometimes overnight, and keep it that way. Performance is guaranteed when sized, installed and operated according to our instructions.