Joepoe Hot Tub Silver Ion Cartridge for Hot Springs Spa- Hot Tub Silver Ion Cartridge Keeps Spa Water Crystal Clear, Spa Mineral Sticks for Hot Tub, Each Filter Last 4 Months (4-Pack, Grey)Brand: Joepoe Color: Gray Features: Efficient Purification Effect: This hot tub silver ion cartridge for hot springs spa can significantly improve the look and feel of the water, reduce impurities in the springs, ensuring that the odor free spa brings you clear water. Easy to Use and Long Lifetime: Just simply drop the hot tub silver ion cartridge into your existing device and let the spa mineral sticks for hot tub do their work. Each spa mineral