From the combined hot temperatures and high powered propulsion water flow to the intimate bathing environment, the filtration needs of a spa are very specific and fundamentally different in many ways from pool filtration. Spa and pool replacement filter cartridges have always been clumped together using the same design and materials for both environments. As the industry leader in science and innovation, Pleatco set out to research, develop and successfully create the world's first and only premium replacement filter cartridges scientifically engineered just for spas!