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Freeflow & Lifesmart Spas Filters

Freeflow Spas and Lifesmart hot tubs (the Costco and big-box lines) are built by Watkins and share one main filter: the 42 sq ft screw-in with a closed top and a tether. Earlier Freeflow tubs used a taller open-top 45, and the small tubs a short 25. All three thread in on a 2″ fitting; the top tells them apart.

Find your Freeflow or Lifesmart filter in 10 seconds

All three cartridges are offered in ProAqua (high-flow) and Darlly, drop-shipped from US stock. Not sure which top yours has? Send a photo through the form below.

Shop: All Hot Tub Filters | Ego3 Reusable Filters | Hot Spring Filters

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✅ Not Sure It Fits? Verify Before Ordering

Hot tub filter fitment varies by spa brand, model, year, filter size, thread style and top/bottom style.

To confirm the correct replacement, send clear photos of:

  • The label or end cap of your current filter
  • Your spa serial number sticker
  • The filter well with the filter removed (so we can see the fitting)

EZ Hot Tub Parts confirms fitment before you order, so you do not pay return freight on a wrong filter.

Freeflow and Lifesmart filter buying guide

42 sq ft, closed top with tether (the Lifesmart filter). 5-1/4″ across, 9-3/8″ long, 2″ MPT thread (Watkins 303279, Pleatco PFF42TC-P4, Unicel 5CH-37, Filbur FC-2402, Lifesmart LSX1057). Fits Lifesmart LS100, LS100DX, LS100 Plus, LS200, LS300 Plus, LS350, LS350DX, LS400DX, LS450DX, LS500 Plus, LS550 Plus, LS600DX, LS700DX, Sereno, Tierra and Leganza, plus Freeflow, Fantasy and AquaTerra tubs with the same well. ProAqua and Darlly on the Lifesmart page; the Freeflow-labelled ProAqua / Darlly listings are the same cartridge.

45 sq ft, open top. 5-5/16″ across, 10″ long, 2″ MPT (Pleatco PFF50P, Unicel 5CH-45, Filbur FC-2401) — the earlier Freeflow cartridge without the tether: ProAqua / Darlly.

25 sq ft, closed top. 4-15/16″ across, 6-5/8″ long, 2″ MPT (Pleatco PFF25TC-P4, Unicel 4CH-23, Filbur FC-2400) — the small Freeflow tubs: ProAqua / Darlly.

Not sure which filter brand is right for you? Compare Hurricane, OEM Factory Direct, Pleatco, ProAqua, Darlly and Ego3.

Keep your filters working longer: High Pressure Filter Nozzle | Filter Cleaner | Water Care — and every order over $99 ships free, so a spare set plus cleaner usually rides along at no extra cost.

Confirm your Freeflow / Lifesmart filter: Lifesmart 42 (ProAqua) | Lifesmart 42 (Darlly) | Freeflow 45 Open Top | Freeflow 25 Closed Top

Freeflow and Lifesmart filter questions

What filter does a Lifesmart LS600DX / LS450DX / LS100 use?

The 42 sq ft closed-top cartridge with the tether — Watkins 303279, Pleatco PFF42TC-P4, Unicel 5CH-37. One cartridge fits the whole Lifesmart DX and Plus range plus Sereno, Tierra and Leganza. It is the first card on this page.

Are Freeflow and Lifesmart filters the same?

For the 42 sq ft tethered cartridge, yes — both brands are Watkins-built and use the same filter well. Earlier Freeflow tubs used the taller open-top 45 sq ft and the small tubs the short 25 sq ft, which Lifesmart did not.

How do I tell the 42 and the 45 apart?

The top. A solid closed cap with a tether loop is the 42 (9-3/8″ long). An open top with no cap is the 45 (10″ long). Both are about 5-1/4″ across and both thread onto the same 2″ fitting, so the top is the only reliable check.

How often should I replace a Lifesmart hot tub filter?

Every 12 months with a rinse every 2–4 weeks and a monthly soak in filter cleaner. These are single-cartridge tubs, so a spare to rotate is worth keeping.

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