Caldera 31489 | 30 sq ft Spa Filter Cartridge

By Caldera
SKU: 31489
$31.99

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Check out the Filter Guide to see if this filter fits your hot tub model.

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Description

TheĀ Caldera 31489 filter cartridgeĀ deliversĀ 30 square feetĀ of pleated filtration for cleaner, clearer spa water. It's one of the mostĀ widely compatible cartridgesĀ in the Watkins family of spa brands, serving a broad range of models across decades of production — so it's a dependable replacement to keep on hand.

Filtration is the quiet backbone of good spa water. Every soak leaves behindĀ body oils, lotions, hair, and fine debris, and the cartridge is what removes all of it before it clouds the water, feeds bacteria, or coats your plumbing. When a filter is worn or clogged, the effects spread everywhere: dull water, higher chemical use, softer jets, and aĀ pump and heater strainingĀ against restricted flow.

This is the compactĀ 30 square foot size — roughly 6 inches across and 10-1/2 inches tall, with open ends top and bottom. Many spas that use this cartridge runĀ more than one at a time, so the set works together to handle the full filtration load. Like all Caldera filters, it'sĀ made in the USA.

Pro Tip:Ā Check how many cartridges your spa uses before you order. Spas built around this 30 square foot size very often run a set of two or three rather than a single filter, and they should always be replaced together. Pairing one new cartridge with older ones leaves the fresh filter doing more than its share and gives you uneven filtration across the set.

Brand

CalderaĀ®

Key Features
  • 30 sq ft of filtration — full factory-spec filtration area per cartridge
  • Pleated media — maximizes filtering surface for efficient, thorough filtration
  • Better water clarity — captures oils, debris, hair, and fine particles
  • Widely compatible — one of the most cross-referenced cartridges in the Watkins family
  • Open top and bottom — simple drop-in installation
  • Made in the USA — like all Caldera filters
How It Works

Water is drawn through the cartridge's pleated media as your spa circulates.Ā Pleating is what creates the capacity: folding the fabric back and forth packsĀ 30 square feetĀ of filtering surface into a cartridge just over 10 inches tall. That surface area means water passes throughĀ more slowly and thoroughly — capturing finer particles — and it means the filter holds far more debris before flow starts to drop off.

Flow matters as much as capture. A cartridge has toĀ filter effectively without choking flow, because your circulation and jet systems were engineered around a specific filtration area and a specific amount of resistance. That's why matching the correct cartridge size to your spa matters more than simply finding one that physically fits the opening.

Pro Tip: A clean filter protects your equipment, not just your water. As the pleats load up with body oils, your pump has to work harder against the restriction, and reduced flow across the heater can trigger flow-related errors. Regular rinsing and periodic deep cleaning is the cheapest protection there is for the expensive parts of your spa.

Directions for Use

Installation

  1. Turn off power to the spa at the breaker before servicing the filter compartment.
  2. Open the filter lid and clear any debris from the compartment.
  3. Remove the old cartridge(s), noting orientation and how many your spa uses.
  4. Seat each new cartridge squarely in place, fully seated top and bottom. Handle it carefully to avoid creasing the pleats.
  5. Replace the full set at the same timeĀ so all cartridges wear evenly.
  6. Close the lid, restore power, and run the circulation to confirm normal flow.

Routine Cleaning

  1. Every two to four weeks:Ā remove the cartridge and spray it thoroughly with a garden hose, working between the pleats from top to bottom.
  2. Periodically:Ā soak or treat the cartridge with a dedicated filter cleaner to dissolve the body oils and buildup a rinse can't remove, then rinse it off.
  3. Let it dry fullyĀ before returning it to service whenever possible.

Replace the cartridge when the pleats are torn, flattened, or permanently discolored, or when cleaning no longer restores flow and clarity.

Pro Tip: If your spa uses multiple filters, buy a spare set and rotate. Filters clean best when they can dry completely, and a proper chemical soak takes hours. With a second set on hand you can swap in clean cartridges immediately and let the others soak and dry on your own schedule — your spa never runs on dirty filters, and every cartridge lasts longer.

Specifications
  • Brand:Ā Caldera Spas (Watkins Wellness)
  • Part Number:Ā 31489
  • Cross-References:Ā Unicel C-6430 (also C-6330, C-6430RA), Pleatco PWK30 (also PWK30-4, PWK30-M), Filbur FC-3915
  • Also Cross-Listed With:Ā Watkins part numbers 71825 and 71826
  • Product Type:Ā Replacement spa filter cartridge
  • Filtration Area:Ā 30 sq ft
  • Media:Ā Pleated polyester
  • Outer Diameter:Ā Approx. 6 in
  • Length:Ā 10-1/2 in
  • Top:Ā Open, approx. 1-15/16 in
  • Bottom:Ā Open, approx. 1-15/16 in
  • Quantity Needed:Ā Many spas in this size class use two or three cartridges — confirm before ordering
  • Cleaning:Ā Rinse with a hose every two to four weeks; deep clean periodically with filter cleaner
  • Replace When:Ā Pleats are torn, flattened, or permanently discolored, or cleaning no longer restores flow
  • Origin:Ā Made in the USA
  • Shipping:Ā Standard ground; not classified as a hazardous material
Compatibility

The 31489 is aĀ Watkins-family cartridgeĀ used across a wide range of spas, generally models built from 1990 forward. It's one of the most broadly cross-referenced filters in the category, listed asĀ Unicel C-6430Ā (also C-6330 and C-6430RA),Ā Pleatco PWK30Ā (also PWK30-4 and PWK30-M), andĀ Filbur FC-3915. It is also cross-listed with Watkins part numbersĀ 71825Ā andĀ 71826.

Because this size spans so many models and production years, the surest way to order correctly is toĀ pull your current cartridge and read the part number printed on it, and confirmĀ how many filters your spa takes. Note that some spas in this size class were designed for a ceramic Tri-X cartridge rather than pleated polyester — if your spa uses Tri-X, stay with Tri-X. For upkeep, pair this filter with a dedicatedĀ filter cleanerĀ for periodic deep cleaning.

  • Vacanza Celio 2019-Current
  • Vacanza Tarino 2013-Current

An aftermarket alternative to this filter is Unicel C-6430 Filter Cartridge

Most products purchased from our online shop within the last 30 days are eligible for return. Please review our return policy to see the list of items that cannot be returned.

Some major items that are non-returnable:

  • Gift cards
  • Electronics
  • Pumps / Motors
  • Hot Tubs
  • Closeouts
  • Fireplaces
  • Electric Fireplaces
  • Massage Chairs
  • See return policy below for full list of non-returnables.

CalderaĀ® Brand FAQs

Who makes Caldera Spas?

Caldera Spas was founded in1976and is manufactured by Watkins Wellness, a global industry leader that has built more than one million hot tubs. Caldera is recognized throughout the industry for performance, quality, and customer satisfaction — including thirteen consecutive certifications for excellence in customer satisfaction from the consumer group SpaSearch.

What are the Caldera Spas series?

Caldera offers three primary series. The UtopiaĀ®Series is the flagship line — a hydrotherapy powerhouse with architecturally inspired cabinetry, touchscreen controls, and premium features. The ParadiseĀ®Series blends practical and premium for mid-range luxury. The VacanzaĀ®Series delivers signature Caldera comfort and quality at an exceptional value. Caldera also offers a cold plunge.

Which filter does my Caldera spa use?

It depends on your series, model, and year. Caldera uses several different cartridges across its lineup, and even within the same model line the filter can change by year. The most reliable method is to pull your current filter and read the part number printed on it, or check your owner's manual. Also confirm how many cartridgesyour spa takes, since some models use more than one.

How often should I clean and replace my Caldera filter?

As a general rule,rinse with a garden hose every two to four weeks, working between the pleats, and deep clean periodically with a dedicated filter cleaner to dissolve the body oils a rinse can't remove. Replace the cartridge when the pleats are torn, flattened, or permanently discolored, or when cleaning no longer restores flow and water clarity.

Are genuine Caldera filters worth it compared to aftermarket?

Factory-original filters are built to the exact dimensions, filtration area, and flow characteristics your spa's circulation and jet systems were engineered around. An aftermarket filter that fits the opening may still restrict flow or filter less effectively, making your pump work harder and leaving your water less clear. Caldera filters use heavy-duty polyester designed to last far longer than cheaper alternatives, and they're made in the USA.

What water care system do Caldera spas use?

It varies by series. UtopiaĀ® and ParadiseĀ® Series spas are designed for the FreshWaterĀ® Salt System, which produces longer-lasting, natural-feeling water with less maintenance — and FreshWaterĀ® IQ adds in-line self-monitoring that tells you what the water needs. VacanzaĀ® Series spas typically use FROGĀ® water care systems. Whichever system you run, clean filters and a consistent routine are what keep the water clear.

About CalderaĀ®

Founded inĀ 1976,Ā CalderaĀ® SpasĀ is one of the most heralded and trusted spa brands in the world. Caldera is manufactured byĀ Watkins Wellness — the global industry leader that has built more thanĀ one million hot tubs — and is recognized throughout the industry for performance, quality, and customer satisfaction.

What sets a Caldera apart is a relentless focus on how it actually feels to use. Comfort is the essential element: deep, cradling seats and a textured Foot Ridge® keep you relaxed and seated even under powerful jets, perfectly positioned hydrotherapy melts tension away, and a whisper-quiet sound-dampening design lets you actually unwind. Every detail is crafted to awaken the senses, from rich colors and contemporary cabinet styles to the organic contours of the sculpted seats. It's the signature blend Caldera owners know as Pure Comfort®, Pure Performance®, and Pure Style®.

The lineup spans three series — the flagshipĀ Utopia® hydrotherapy powerhouse, the premium-yet-practicalĀ ParadiseĀ®, and the exceptional-valueĀ Vacanza® — all engineered for comfort, efficient energy use, and simple maintenance. Genuine Caldera parts and filters are built to the same standard as the spas themselves, so your equipment keeps performing exactly as designed.Ā Come to Caldera. Come to life.