The S7M120 and S7M400 models share a common 21" tank design, while the S8M150 and S8M500 models are equipped with a larger 25" tank. This shared tank architecture within each series creates a versatile system that allows for cartridge interchangeability.

Upgrade Options

Due to this compatibility, pool owners can upgrade or downgrade their filtration capacity as needed. For example, S7M120 owners seeking enhanced filtration or wanting to reduce filter maintenance frequency can upgrade to S7M400 cartridges. This upgrade provides a significant 33% increase in filtration capacity, expanding from 300 to 400 square feet of filter fabric area.

Downgrade Flexibility

Conversely, if you find your current filter system excessive for your pool's needs or wish to reduce cartridge costs, downgrades are equally possible. S7M400 owners can switch to S7M120 cartridges, while S8M500 users have the option to transition to S8M150 cartridges for more cost-effective maintenance.

D.E. Filter Compatibility

The System 3 D.E. cartridge models (S7MD60 and S7MD72) also offer interchangeable capabilities, both utilizing 21" tanks. This compatibility extends beyond just D.E. filters - a recent customer successfully converted their S7MD60 from D.E. filtration by replacing the D.E. cartridge with two S7M400 cartridges, demonstrating the versatility of the 21" tank shared across all S7M* series filters.