Unicel C-7466 | 65 sq ft Sundance Spa Filter Cartridge

By Unicel
SKU: C-7466
$93.99

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Description

The Unicel C-7466 is a 65 square foot replacement cartridge for Sundance and Sweetwater spas, replacing OEM part number 6540-481. It carries 164 pleats across a wide 7-1/2" body, and it is distinguished by a closed castle top — a sealed end cap with a crenellated rim, notched like the battlements on a castle wall, which is where the name comes from.

That closed top is not decoration. It means water has exactly one way out of this cartridge: down through the core and out the open bottom into the suction line. On a cartridge with two open ends, water can exit either way and the filter simply sits in the flow path. Here the cartridge is committed to a single direction, and the castellated rim locates it in the housing so it stays centered and square while that flow pulls on it. The notches let water move freely around the top of the cartridge rather than letting it dam up against a solid rim.

The practical case for this cartridge is capacity in a wide, relatively short package. Sixty-five square feet from a body just 14-3/4" tall is achieved through diameter rather than height — the 7-1/2" width gives roughly 23 inches of circumference for those 164 pleats to work with, so the folds can stay generously spaced. That matters more than it sounds. Widely spaced pleats release trapped debris far more readily during cleaning than tightly packed ones, which means this cartridge recovers closer to full performance after each wash and holds that recovery over more cleaning cycles.

Media is Unicel's standard 3 oz Reemay polyester — one hundred percent spunbonded polyester over a solid injection-molded core, with chemical-resistant end caps molded to an exact OEM fit, capturing suspended particles down to roughly 20 microns. Made in the USA by Meissner Manufacturing, with more than 45 years behind the Unicel name.

Pro Tip: If you measured your old cartridge and got 8" instead of 7-1/2", this is still your filter. Sundance produced this cartridge position in two outer diameters over the years, and Unicel specifies this single part to replace both the 7-1/2" and the 8" OD versions. It is a deliberate consolidation on Unicel's part, not an approximation. The dimensions that actually determine fit here are the closed castle top and the open bottom sized for a 2" system — match those and the half-inch of outer diameter takes care of itself.

Brand

UNICEL®

Key Features
  • Replaces both 7-1/2" and 8" OD Sundance cartridges: One part number covers two outer diameters that Sundance used across production, removing a common source of ordering confusion.
  • 65 square feet of filtration area: Substantial capacity that clogs slowly, holds flow steady between cleanings, and reduces strain on the circulation pump.
  • 164 pleats across a wide 7-1/2" body: Generous pleat spacing that holds real capacity while still releasing trapped debris readily during cleaning.
  • Closed castle top end cap: A sealed, crenellated cap that locates and centers the cartridge in the housing while letting water move freely around it, and commits all filtered flow to the bottom outlet.
  • Open 2-5/8" bottom: Sized for Sundance's 2" system, seating over the suction fitting for a clean drop-in installation with nothing to thread or align.
  • 3 oz Reemay polyester media: One hundred percent polyester with strong chemical resistance, balancing dirt-holding capacity against cleanability so the cartridge recovers well through repeated wash cycles.
  • Approximately 20-micron filtration: Captures the fine suspended particles responsible for cloudy, hazy water.
  • Solid injection-molded core: Holds pleat geometry under sustained one-directional suction and resists the collapse that causes channeling.
  • Made in the USA: Manufactured by Meissner Manufacturing to meet or exceed OEM specification.
How It Works

The cartridge drops into the filter compartment with its open bottom seated over the suction fitting and the castle top facing up. When the circulation pump runs, it draws water out through that bottom opening, dropping the pressure inside the hollow core below that of the surrounding spa water. The difference pushes water inward through the pleated media from every direction at once — across the full 7-1/2" circumference and the entire 14-3/4" height. Filtered water collects in the core and travels down and out into the suction plumbing.

Because the top is sealed, that downward path is the only one available. On a cartridge with two open ends, flow distributes between both outlets and the pressure gradient inside the core is relatively even. Here the gradient runs in one direction, which produces slightly stronger draw near the bottom outlet and means the lower portion of the media tends to load a little faster than the top. Not dramatically — the wide diameter keeps face velocity low — but enough that it is worth knowing when you decide how thoroughly to rinse each end.

The 164-pleat count is a deliberately moderate choice. A wide 7-1/2" cartridge offers roughly 23 inches of circumference to fold media into, so hitting 65 square feet does not require crowding the pleats the way a narrow-body cartridge would. The payoff is cleanability: wider gaps mean a garden hose can actually reach the base of each fold, so debris rinses out rather than compacting. A cartridge that genuinely cleans back to near-new performance is worth more over its life than one with a higher pleat count that never quite recovers.

Debris loads into the depth of the polyester fibers rather than sitting on the surface, which is why a cartridge that still looks reasonably clean can already be measurably restricted. Declining jet pressure is the most reliable early signal that a cleaning is due.

Pro Tip: Clean the notches in the castle top every time. The crenellated rim is a natural trap for hair, lint, and long fibers, which wrap around the raised sections and knot into the gaps between them. It is the easiest part of the cartridge to overlook because it does not look like filter media and it sits at the end you are not focused on. Debris packed into those notches restricts water movement around the top of the cartridge and, worse, can prevent the cartridge from seating square in the housing. Run a stream of water through each notch and pick out anything wrapped around the rim before you reinstall.

Directions for Use

Installation

  1. Turn the spa off at the breaker before opening the filter compartment.
  2. Remove the filter lid and lift the old cartridge straight up and out. Let it drain as you lift — a loaded cartridge this size holds a surprising amount of water and debris, and pulling it out fast dumps that load back into the well.
  3. Inspect the compartment and the suction fitting. Clear away hair, grit, and debris collected in the well, and check that the sealing surface at the base is smooth and undamaged.
  4. Lower the new cartridge in with the castle top facing up and the open bottom seating over the suction fitting.
  5. Press down gently until it seats fully. Confirm it sits square and does not rock or lean.
  6. Replace the lid, restore power at the breaker, and run a full circulation cycle.
  7. Verify normal jet pressure and flow. A clear improvement over the old cartridge is expected.

Routine Cleaning

  • Every 2 to 4 weeks: Remove and rinse with a garden hose. Spray downward into the pleats at an angle, rotating the cartridge steadily so the full 7-1/2" circumference gets direct attention. The wide pleat spacing works in your favor here — a hose can actually reach the base of each fold, so a proper rinse is genuinely effective on this cartridge.
  • Clean the castle notches at every rinse. Flush each gap in the crenellated rim and pick out any hair or fibers wrapped around the raised sections.
  • Every 3 months: Deep-soak in a dedicated spa filter cleaning solution to dissolve body oils, lotion residue, and mineral scale that rinsing cannot remove. Rinse thoroughly afterward — cleaner residue left in the media is a common and entirely preventable cause of foaming.
  • At every drain and refill: Deep-clean the cartridge before it goes back into fresh water. Installing a loaded filter into a freshly filled spa gives back most of the benefit of the refill.
  • Rotate two cartridges if you can: A spare lets you install the clean one immediately while the other dries completely. A fully dried cartridge releases trapped debris far more easily on the next rinse, and rotating roughly doubles the useful life of both.

Important Cautions

  • Do not use a pressure washer. High-pressure spray tears media fibers and destroys pleat geometry, often without visible damage, and torn media passes unfiltered water straight through. The castle rim is also easily chipped by concentrated high-pressure spray.
  • Do not install the cartridge upside down. The closed castle top must face up — inverted, the sealed cap blocks the suction fitting and the spa will lose flow.
  • Do not clean with dish soap, laundry detergent, or household cleaners. These leave residues that foam persistently and are difficult to rinse out.
  • Do not force a cartridge that does not seat easily. Resistance means a fitment mismatch, and forcing it deforms the end cap and creates a bypass path.
  • Do not run the spa without a cartridge installed, even briefly. Debris drawn directly into the pump can cause damage costing far more than a filter.
  • Do not boil, bleach, or machine-wash the cartridge.

When to Replace

Replace the cartridge when you see torn or separated media, cracked or deformed end caps, a soft or collapsing core, pleats that have permanently lost their shape, staining that no longer responds to a deep soak, or a persistent drop in flow that thorough cleaning no longer restores. On this cartridge, pay particular attention to the castle rim: chipped, broken, or missing crenellations mean the cartridge can no longer locate itself squarely in the housing, and a cartridge that sits crooked will not seal at the bottom regardless of how good the media looks. Most spa owners under typical use replace every 12 to 18 months.

Specifications
  • Brand: Unicel
  • Manufacturer: Meissner Manufacturing Co., Inc.
  • Part Number: C-7466
  • Product Type: Replacement spa filter cartridge, drop-in
  • Filtration Area: 65 sq. ft.
  • Pleat Count: 164
  • Filter Media: 3 oz. Reemay polyester
  • Micron Rating: Approximately 20 microns
  • Outer Diameter: 7-1/2" — this part also replaces the 8" OD Sundance cartridge
  • Length: 14-3/4"
  • Top End Cap: Closed castle
  • Bottom End Cap: Open, 2-5/8" inner diameter, for 2" systems
  • Core: Solid injection-molded, full-length
  • End Cap Material: Chemical-resistant molded plastic, exact OEM fit
  • Replaces OEM: Sundance Spas 6540-481
  • Cross-References: Pleatco PSD65-2, Filbur FC-2740, Aladdin 16503, RJ Filtration AK-6042, Darlly 70654
  • Quantity Per Spa: Typically one; verify your filter compartment configuration
  • Typical Service Life: 12 to 18 months with routine cleaning
  • Cleaning Method: Hose rinse every 2 to 4 weeks, including the castle notches; chemical soak every 3 months. Do not pressure wash.
  • Installation: Drop-in, castle top facing up. Nothing to thread or tighten.
  • Not Compatible With: Sundance systems using threaded cartridges, handled cartridges, or multi-piece filter assemblies
  • Origin: Made in the USA
  • Shipping: Standard ground; not classified as a hazardous material
Compatibility

Replaces This OEM Part Number

  • Sundance Spas 6540-481

Cross-Reference Part Numbers

  • Pleatco PSD65-2
  • Filbur FC-2740
  • Aladdin 16503
  • RJ Filtration / Baleen AK-6042
  • Darlly 70654

Spa Brands Using This Cartridge

  • Sundance Spas — the 65 sq ft filter position on 2" systems
  • Sweetwater Spas

An Important Note for Sundance Owners

Sundance has used several genuinely different filtration architectures across its lineup — single drop-in cartridges, threaded cartridges, and multi-piece assemblies where a second component mounts to the first. Knowing you own a Sundance narrows the field far less than you would expect, and cartridges from different Sundance systems are not interchangeable even when their square footage matches. This cartridge is the single-piece drop-in for 2" systems: closed castle top, open bottom, nothing threaded and nothing that attaches to it. If your existing cartridge has a threaded fitting, a handle, or a second cartridge mounted to one end, you have a different system and need a different part.

How to Confirm Fitment

Verify all four against your existing cartridge before ordering:

  • Top end cap: Closed castle — sealed, with a notched or crenellated rim. This is the single most distinctive identifying feature.
  • Bottom opening: Open, 2-5/8" inner diameter, sized for a 2" system.
  • Overall length: 14-3/4", measured end cap to end cap.
  • Outer diameter: 7-1/2" — or 8". Both are covered by this part.

Pro Tip: On this cartridge, the bottom opening is the measurement that matters most, so measure it carefully. Outer diameter is forgiving here, since one part covers two sizes. The bottom inner diameter is not: it determines whether the cartridge seats correctly over the suction fitting, and a cartridge that does not seat leaves a gap for unfiltered water to bypass the media entirely. Measure across the inside of the opening, not the outside of the end cap. If your reading comes out meaningfully different from 2-5/8", you likely have a cartridge from a different Sundance system — our team can identify the right one from your spa's serial number.

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.

UNICEL® 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 useReemay® 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 UNICEL®

Unicel 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, Richard T. Meissner 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 producing cartridge filters for the industry's original equipment manufacturers.

That's the detail that matters most: Unicel was building the filters that went into new spas long before it sold a replacement. In 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 spans nearly 500 products, all manufactured in 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 with chemical-resistant end caps for an exact fit, high-capacity filter media, uniform pleats for optimal flow, and a solid core that holds its shape under pressure. Meissner Mfg. Co., Inc. remains owned and operated by the Meissner family, still recognized for quality and service. American-made products, world-class service.