Unicel 5CH-35 | 35 sq ft Top Load Spa Filter

By Unicel
SKU: 5CH-35
$44.99

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

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Description

The Unicel 5CH-35 is a top-load spa filter cartridge delivering 35 square feet of filtration across 203 pleats of Reemay® 2033 polyester media. Built to meet or exceed OEM specifications, it's a direct replacement for Elite Spas by Maax®, Marquis®, and other systems using this cartridge.

Filtration is the quiet backbone of clean spa water. Every soak leaves behind 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 a pump and heater straining against restricted flow.

What stands out here is the pleat density. At 203 pleats in a compact cartridge just 8 inches tall, the 5CH-35 packs a remarkable amount of filtering surface into a small footprint — more surface means more places to trap debris and more time between cleanings. The top-load design makes upkeep genuinely easy: a semi-circular handle molded into the top lets you grip and lift, while the 1-1/2 inch male pipe thread bottom screws securely into the housing for a tight, leak-free seal. Made in the USA.

Pro Tip: Same square footage does not mean same filter — check the part number. Unicel makes more than one 35 sq ft cartridge, and they are not interchangeable: the 5CH-352, for example, is also rated 35 sq ft but is 12-1/2 inches long with a bar handle and a 2-inch thread, where this one is 8 inches with a semi-circular handle and a 1-1/2 inch thread. Read the number printed on your current cartridge before you order.

Brand

UNICEL®

Key Features
  • 35 sq ft of filtration — full OEM-spec filtration area across 203 pleats
  • Dense pleat count — 203 pleats packed into a compact 8-inch cartridge
  • Top-load design — semi-circular handle makes removal and cleaning effortless
  • 1-1/2 in MPT threaded bottom — screws in for a secure, leak-free connection
  • Reemay 2033 polyester media — balances dirt-holding capacity, cleanability, and chemical resistance
  • 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. Pleating creates the capacity: folding the fabric into 203 pleats packs 35 square feet of filtering surface into a cartridge only 5-5/8 inches across and 8 inches tall. More surface means water passes through more slowly and thoroughly, capturing finer particles, and it means the filter holds far more debris before flow starts to drop off.

The media does the rest. Reemay fibers are 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. Just as important is the threaded connection: screwing the cartridge into the housing creates a positive seal, so water is forced through the media rather than slipping around it. A loose or mismatched fitting lets debris bypass the filter entirely, no matter how good the fabric is.

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. Lift the old cartridge out by its handle, unthreading it from the base connection.
  4. Lower the new cartridge in with the threaded end facing down and turn it until the 1-1/2 inch thread is seated snugly. Hand-tight is enough — over-tightening can crack the fitting.
  5. If your spa uses more than one cartridge, replace them at the same time so they wear evenly and flow stays balanced.
  6. Close the lid, restore power, and run the circulation to confirm normal flow.

Routine Cleaning

  1. Every two to four weeks: lift the cartridge out by the handle and rinse gently with a garden hose, working between the pleats from top to bottom. A soft brush cleaning tool helps.
  2. Periodically: 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 fully before returning it to service whenever possible.

When to Replace

  • The cycle between cleanings gets noticeably shorter
  • Low water flow or high differential pressure
  • The media has a tear
  • The center core collapses

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

Pro Tip: With 203 pleats packed into a small cartridge, take your time rinsing. A dense pleat count is what gives this filter its capacity, but it also means the folds sit close together and debris settles deep between them. Working the hose stream slowly down each pleat, all the way around, removes far more than a quick pass over the outside — and it noticeably extends how long the cartridge lasts.

Specifications
  • Brand: Unicel (Meissner Mfg. Co., Inc.)
  • Part Number: 5CH-35
  • Product Type: Top-load replacement spa filter cartridge
  • Filtration Area: 35 sq ft
  • Pleat Count: 203
  • Media: Reemay 2033 spunbonded polyester, 3 oz basis weight
  • Outer Diameter: 5-5/8 in
  • Length: 8 in
  • Top: Semi-circular handle
  • Bottom: 1-1/2 in male thread / MPT
  • End Caps: Durable plastic, chemical-resistant, exact OEM fit
  • Fits: Elite Spas by Maax, Marquis spas, and other systems using this cartridge
  • Cross-References: Filbur FC-0300, Darlly 50353, Filters XLS-526, AK-90109
  • Not the Same As: Unicel 5CH-352 — also 35 sq ft, but 12-1/2 in long with a bar handle and 2 in thread
  • Thread Note: MPT version; a separate 5CH-35SAE variant uses an SAE thread
  • Cleaning: Rinse gently with a garden hose every two to four weeks; deep clean periodically with filter cleaner. Do not pressure wash.
  • Origin: Made in the USA
  • Shipping: Standard ground; not classified as a hazardous material

  • Outer Diameter: 5-5/8"
  • Length: 8"
  • Top End Cap: semi-circular handle
  • Bottom End Cap: 1-1/2" male thread/MPT
  • Pleat Count: 203
  • Media: 3 oz.
  • Filtration Square Footage: 35 sq. ft
Compatibility

The 5CH-35 fits Elite Spas by Maax® and Marquis® spa systems, along with other spas built around this top-load cartridge. It's cross-referenced as Filbur FC-0300, Darlly 50353, Filters XLS-526, and AK-90109.

Before ordering, confirm three things:

  • Thread type — this is the 1-1/2 inch MPT (male pipe thread) version; Unicel also offers a 5CH-35SAE variant with an SAE thread, and the two are not interchangeable
  • Dimensions — 5-5/8 inch diameter, 8 inch length, semi-circular handle on top
  • Quantity — how many cartridges your spa takes, since some systems use more than one

The surest method for all three is to pull your current cartridge and read the part number printed on it. For upkeep, pair it with a dedicated filter cleaner for periodic deep cleaning.

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.