![Spa Frog 4-month Refill Mineral Cartridge](http://hottubspasource.com/cdn/shop/products/spa-frog-floating-system_2c52fd95-4128-467c-9ab0-305d01a4ce64_{width}x.jpg?v=1392151811)
Blue in photo. Four month lifespan, same as standard cartridges. Also used in 'in-line' systems in numerous brands.
Listed as minimum price allowed!
Blue in photo. Four month lifespan, same as standard cartridges. Also used in 'in-line' systems in numerous brands.
Listed as minimum price allowed!