Hard water is characterized by its dissolved high mineral content, mainly consisting of calcium and magnesium. It is an extremely common issue, with 85% of the water in the U.S. being classified as hard water. While hard water does not necessarily pose a health risk, it is extremely harmful for appliances exposed to the mineral elements.
Repeated exposure can cause an off-white scale build-up in appliances and pipes and ultimately decrease their effectiveness and even shorten their useful life. A demineralization filter is an excellent way to prevent the "white dust" and lime scale residue build-up that results from hard water, with the added benefit of protecting and extending the life of your humidifier.
The Crane HS-1931 License Filter is compatible with both the Crane SpongeBob (EE-5063) and Hello Kitty (EE-4109) character humidifiers.