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Mar 05, 2026 - 01:12 PM
If you want to convert that System 3 tank to use cartridge elements (inner and outer), you need the separate Modular Media (cartridge) kit, not just a different pair of cartridges. On System 3, the DE and the cartridge versions use different internal hardware, so you can’t simply drop a pair of S7M120 (cartridge) elements into an S7MD72 and have it work safely or correctly.
Because conversion requires the specific Sta‑Rite/Pentair “System 3 Modular DE Conversion Kit” and matching media, I’d strongly recommend either:
Other things to consider... There is a conversion kit available, as mentioned above; however, this is not a very common part, and availability might be an issue. Also, time and labor might play into your decision. Will you be doing this yourself, or would you have a technician perform this conversion for you?
Because conversion requires the specific Sta‑Rite/Pentair “System 3 Modular DE Conversion Kit” and matching media, I’d strongly recommend either:
- Replacing with the correct DE module: 25023‑0172S (72 sq ft DE element for S7MD72), or
- Swapping the entire filter to the cartridge model (e.g., S7M120) if you want to go to inner/outer cartridges, rather than trying to mix parts inside your DE tank.
Other things to consider... There is a conversion kit available, as mentioned above; however, this is not a very common part, and availability might be an issue. Also, time and labor might play into your decision. Will you be doing this yourself, or would you have a technician perform this conversion for you?
