Unicel C-8465 | 65 sq ft Hot Spring Spa Filter

By Unicel
SKU: C-8465
$78.99

Let's Ensure This Fits Your Model

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

If you have questions, call us at (208) 973-1384 or send us an email to hello@leisuretimeinc.com

If possible, please have your hot tub’s serial number ready when you contact our team.

Description

TheĀ Unicel C-8465Ā deliversĀ 65 square feetĀ of filtration acrossĀ 234 uniform pleats, capturing debris and particles down to an average ofĀ 20 microns. Built toĀ meet or exceed OEM specifications, it's a direct replacement for a wide range of Hot Spring, Caldera, and Tiger River cartridges.

Filtration is the quiet backbone of clean 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.

What separates a Unicel from a bargain cartridge is what it's built from. The media isĀ ReemayĀ® polyester — a spunbonded, trilobal fiber whose three-lobed shape presents substantiallyĀ more surface areaĀ than standard rounded fibers, balancing dirt-holding capacity, cleanability, and chemical resistance. AddĀ sharp, uniform pleat foldsĀ that maximize flow and minimize pressure loss,Ā chemical-resistant end capsĀ with an exact OEM fit, and aĀ solid coreĀ that holds its shape under pressure, and you get a cartridge that performs through cleaning after cleaning. Made in the USA.

Pro Tip:Ā Twenty microns is finer than you can see. A human hair is roughly 70 microns across, so this cartridge is capturing particles several times smaller than anything visible to the naked eye. That's exactly why water can look clear and still benefit from a fresh filter — the difference between "clear" and genuinely polished water happens at a scale you'll never spot by looking.

Brand

UNICELĀ®

Key Features
  • 65 sq ft of filtration — full OEM-spec filtration area across 234 pleats
  • Captures down to 20 microns — removes particles far finer than the eye can see
  • Reemay polyester media — balances dirt-holding capacity, cleanability, and chemical resistance
  • Sharp, uniform pleats — maximize water flow and minimize pressure loss
  • Chemical-resistant end caps — durable plastic with an exact OEM fit and 3-inch open configuration
  • Made in the USA — built to meet or exceed OEM standards
How It Works

Water is drawn through the cartridge's pleated media as your spa circulates.Ā Pleating creates the capacity: folding the fabric into 234 pleats packsĀ 65 square feetĀ of filtering surface into a cartridge 8-1/2 inches across and about 10-1/2 inches tall. More surface 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.

Two design details do the heavy lifting. First, theĀ ReemayĀ media: its fibers areĀ trilobal — three-lobed in cross-section rather than round — which packs considerably more surface area into the same material, giving more places for dirt to be captured and a smooth surface that releases it readily when rinsed. Second, theĀ pleat geometry: sharp, evenly spaced folds let water reach the full depth of every pleat, so the entire surface actually does filtering work instead of some folds being pinched shut. That's whatĀ maximizes flow, minimizes pressure loss, and lets the cartridge hold more debris between cleanings.

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, noting its orientation.
  4. Seat the new cartridge squarely in the filter well, fully seated top and bottom.
  5. If your spa uses more than one cartridge,Ā replace them at the same timeĀ so they 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 andĀ rinse gently with a garden hose, working between the pleats from top to bottom. A soft brush cleaning tool helps.
  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.

When to Replace

  • The cycle between cleanings gets noticeablyĀ shorter
  • Low water flowĀ or high differential pressure
  • The media has aĀ tear
  • TheĀ center core collapses

Cartridge life depends on routine maintenance and your spa's water chemistry.

Pro Tip: Skip the pressure washer — a garden hose is the right tool. It's tempting to blast a dirty cartridge clean, but high-pressure water drives debris deeper into the media and can tear the pleats or damage the fibers, permanently reducing how well the filter works. Steady hose pressure worked patiently down each pleat gets it cleaner and keeps the cartridge intact far longer.

Specifications
  • Brand:Ā Unicel (Meissner Mfg. Co., Inc.)
  • Part Number:Ā C-8465
  • Product Type:Ā Replacement spa filter cartridge
  • Filtration Area:Ā 65 sq ft
  • Pleat Count:Ā 234
  • Filtration Rating:Ā Captures debris to an average of 20 microns
  • Media:Ā Reemay spunbonded polyester, 3 oz basis weight
  • Outer Diameter:Ā 8-1/2 in
  • Length:Ā 10-1/2 in
  • Top End Cap:Ā Open, 3 in inner diameter
  • Bottom End Cap:Ā Open, 3 in inner diameter
  • End Caps:Ā Durable plastic, chemical-resistant, exact OEM fit
  • Replaces:Ā Hot Spring/Watkins 31114, 71827, 71828; Caldera Spas 76136; Tiger River 31114
  • Cross-References:Ā Pleatco PWK65, Filbur FC-3960
  • Cleaning:Ā Rinse gently with a garden hose every two to four weeks; deep clean periodically with filter cleaner. Do not pressure wash.
  • Origin:Ā Made in the USA
  • Shipping:Ā Standard ground; not classified as a hazardous material

  • Outer Diameter: 8-1/2"
  • Length: 10-1/2"
  • Top End Cap: 3" / open
  • Bottom End Cap: 3" / open
  • Pleat Count: 234
  • Media: 3 oz.
  • Filtration Square Footage: 65 sq. ft
Compatibility

The C-8465 fits a broad range ofĀ Watkins-familyĀ spas — Hot SpringĀ®,Ā CalderaĀ®, andĀ Tiger River® models — and serves as a direct replacement for these OEM cartridges:

  • Hot Spring / Watkins:Ā 31114, 71827, 71828
  • Caldera Spas:Ā 76136
  • Tiger River:Ā 31114

It's also cross-referenced asĀ Pleatco PWK65Ā andĀ Filbur FC-3960.

Because this size spans several brands and many model years, the surest way to order correctly is toĀ read the part number off your current cartridgeĀ or check it against the dimensions below — and confirmĀ how many filters your spa takes. For upkeep, pair it with a dedicatedĀ filter cleanerĀ for periodic deep cleaning.

  • Vacanza Marino 2010-Current
  • Vacanza Palatino 2010-Current
  • Vacanza Vanto 2011-Current
  • Limelight Bolt 2012-2017
  • Limelight Flair 2008-2017
  • Limelight Glow 2008-2017
  • Limelight Pulse 2008-2017
  • Tiger River Bengal M 1997-2010
  • Tiger River Bengal MM 2005-2010
  • Tiger River Caspian CHP 2004-2010
  • Tiger River Caspian CPN 2003
  • Tiger River Khyber L 1994-1996
  • Tiger River Manora MH 1996
  • Tiger River Manora M 1992-1996
  • Tiger River Siberian L 1997-2004
  • Tiger River Sumatran N 1997-2010
  • Tiger River Tondi N 1992-1994
  • Tiger River Tondi PH 1996
  • Tiger River Tondi P 1995-1996
  • Hot Spot La Palma 2008-2009
  • Hot Spot Relay 2010-Current
  • Hot Spot Rhythm 2011-Current
  • Hot Spot Tempo 2010-2019

This is a replacement for the Caldera Vacanza 76136 Filter Cartridge

This is a replacement for the Hot Spring 71827 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.

UNICELĀ® Brand FAQs

Who makes Unicel filters?

Unicel filters are made byMeissner Mfg. Co., Inc., a family business that began as a small contract sewing operation in thelate 1950sand moved into pool filtration through the 1970s. By the end of that decade the company was producing cartridge filters for the industry'soriginal equipment manufacturers, and in1985it introduced the Unicel brand as aftermarket replacements. It's still owned and operated by the Meissner family today.

Are Unicel filters as good as the original manufacturer's filter?

Unicel builds its cartridges tomeet or exceed original equipment specifications— and that's a meaningful distinction here, because the company produced cartridges for the industry's OEMs before it ever launched its own brand. Unicel cartridges usedurable, chemical-resistant end capswith an exact fit,high-capacity media,uniform pleatsfor optimal flow, and asolid corethat resists collapsing under pressure.

Where are Unicel filters made?

Unicel filters are manufactured inCalifornia, with components sourcedexclusively in the United States. The line comprisesnearly 500 products, covering replacement cartridges, D.E. grids, filter discs, and related parts.

How do I find the right Unicel filter for my spa?

Unicel cartridges areinterchangeable with all major filter brands, and each one cross-references to a list of original equipment part numbers. The most reliable method is topull your current cartridge and read the part number printed on it, then match it to the Unicel cross-reference. If the number has worn off,measure your old cartridge— diameter, length, and the size and style of the openings at each end — and match those instead. Also confirmhow many cartridgesyour spa uses.

How long does a Unicel filter last?

Cartridge life depends on how heavily the spa is used, yourwater chemistry, and how consistently you clean the filter. Many Unicel cartridges useReemayĀ® polyester media, whosetrilobal fibersprovide considerably more surface area than standard rounded fibers — which increases dirt-holding capacity and extends the time between cleanings. With regular rinsing and periodic deep cleaning, a well-maintained cartridge commonly serves a year or more.

When should I replace my filter instead of cleaning it?

Replace the cartridge when thecycle between cleanings becomes noticeably shorter, when you seelow water flowor high differential pressure, when the media has atear, or if thecenter core collapses. Pleats that stay permanently flattened or discolored after a proper cleaning are another sign the cartridge has reached the end of its service life.

About UNICELĀ®

UnicelĀ is the nation's leading manufacturer of replacement filter cartridges for pools and spas — and the story behind it is a genuinely American one. In the late 1950s,Ā Richard T. MeissnerĀ started a small part-time contract sewing operation. Through the 1970s, Meissner Mfg. Co., Inc. moved into swimming pool filter bags, then D.E. grid element covering, and by the end of that decade the company was producingĀ cartridge filters for the industry's original equipment manufacturers.

That's the detail that matters most: Unicel wasĀ building the filters that went into new spas long before it sold a replacement. InĀ 1985, the company introduced the UNICEL brand so dealers and technicians could source elements built to O.E.M. specifications from a single place — even for equipment brands they didn't carry. Today the line spansĀ nearly 500 products, all manufactured inĀ California with components sourced exclusively in the USA.

By staying focused on one thing — filtration — Unicel has built deep expertise in a critical corner of the industry, from media development to cartridge design. Every cartridge is built withĀ chemical-resistant end capsĀ for an exact fit,Ā high-capacity filter media,Ā uniform pleatsĀ for optimal flow, and aĀ solid coreĀ that holds its shape under pressure. Meissner Mfg. Co., Inc. remainsĀ owned and operated by the Meissner family, still recognized for quality and service. American-made products, world-class service.