Poolzilla Replacement Inner & Outer Filter Cartridges for Sta‑Rite System 3 S7M120 — 24"×9" & 18"×16", Trilobal Fiber

Poolzilla replacement inner and outer cartridges restore filtration for Sta‑Rite System 3 S7M120, delivering clearer pool water with easy cleaning and reliable fit.

These two OEM‑compatible cartridges (one inner and one outer) are made for the Sta‑Rite System 3 S7M120 modular media filter. Manufactured with a trilobal fiber structure in the United States, they are designed to trap fine particles while resisting clogging and simplifying rinsing compared with older point‑bonded styles. This listing includes the inner cartridge sized 24" long by 9" outer diameter and the outer cartridge sized 18" long by 16" outer diameter, offering a direct swap for model numbers 25021‑0200/25021‑0200S (inner) and 25022‑0201S (outer).

How do these cartridges improve my pool's clarity?

Poolzilla cartridges capture suspended solids such as sand, silt, scale particles and rust that cause cloudy water. The trilobal fiber weave increases surface area, so more debris is intercepted before it reaches the tank bottom. Over time, consistent filtration reduces visible turbidity and can lower taste and odor caused by chlorine byproducts.

• High surface area media for finer particle capture
• Removes sediment, sand, silt and rust particulates
• Helps reduce chlorine taste and odor with regular use

Will these fit my Sta‑Rite System 3 S7M120 without modification?

Yes — the cartridges are manufactured to match the dimensions and design of the original Sta‑Rite System 3 S7M120 replacement parts. They are sold as a set (one inner, one outer) to maintain the filter’s intended flow path and performance. No trimming or adhesive is required when you install them according to your filter's manual.

• Inner cartridge: 24" length × 9" outer diameter × 4" inner diameter
• Outer cartridge: 18" length × 16" outer diameter × 10" inner diameter
• Direct swap for part numbers 25021‑0200/25021‑0200S and 25022‑0201S

How do I clean and maintain these replacement cartridges?

Rinse the cartridges with a garden hose after backwashing to dislodge trapped debris, paying attention to pleat valleys. Periodically soak in a cartridge cleaner to remove oils and scale if you notice reduced flow. Inspect seals and end caps for wear and replace cartridges when pleats become damaged or permanent staining occurs.

• Hose‑off weekly or after heavy debris events
• Use a commercial cartridge soak for oils and mineral buildup
• Replace when pleats tear or flow loss persists after cleaning

What benefits come from the trilobal fiber design?

The trilobal filament geometry increases effective media area and sheds debris more readily than typical point‑bonded cartridges. That design reduces clogging, shortens rinse times, and can extend usable life between replacements. It also maintains structural stability to preserve even flow through the filter.

• Greater filtration area per pleat for improved capture
• Less point bonding = easier cleaning and debris release
• Durable construction for consistent flow and longevity

Who is this for: Poolowners and service technicians who run a Sta‑Rite System 3 S7M120 and need a dependable, easy‑to‑clean cartridge set. These Poolzilla replacements are suited for seasonal maintenance, midseason performance refreshes, or whenever worn cartridges reduce circulation and clarity. If you want American‑made media with a design focused on higher capture efficiency and simplified upkeep, this inner and outer cartridge set provides a practical, drop‑in solution.