REPLACEMENT FILTER for Sundance® Microclean Filter 6540-501 AND 6540-502 4PKListing includes ONE replacement for 6540 501 Microclean Reusable filter (bottom) and FOUR replacements for 6540 502 Microclean Disposable Filters (top) *Adapter not included but can be purchased separately* Replacement Filter For Sundance Spas MicroClean I Filter System. The MicroCleancartridge provides maximum filtration for crystal clear spa water. For use with Sundance 850 & 780 Series Spas. The complete MicroClean I Filter System pictured in