Replace your Master Spa-compatible filter cartridge every 12–18 months under normal use conditions. Heavy usage or high bather loads may require more frequent replacement. Watch for these warning signs: reduced water flow despite cleaning, visible damage to filter pleats, persistent cloudiness, or increased pump pressure. The filter media breaks down over time, even with proper care. When performance declines, it's time for a fresh cartridge. SpiroPure Master Spa-compatible replacements provide factory-spec filtration at significant savings, making scheduled replacement affordable and hassle-free.