Hayward Pool Filter Cartridge Sizing Guide: Measure and Match

A wrong Hayward pool filter cartridge doesn't just waste money. It starves your pump, spikes your pressure gauge, and can turn a routine swap into a weekend-long headache. The real problem? Hayward makes dozens of filter models across multiple series, and the labels that hold the answers tend to fade, peel, or disappear right when you need them most.

This guide walks you through every step from locating your model number to confirming exact cartridge dimensions and placing an order with confidence. By the end, you'll know precisely which replacement fits your housing, whether you go OEM or aftermarket.

What You Need Before You Start

Gather a few things before you head out to the equipment pad. Having everything ready saves you from multiple trips and keeps the process under 15 minutes.

• A tape measure (rigid metal works better than fabric for cartridge diameters)

• Your phone or camera for label photos and quick reference shots

• A flashlight if your equipment pad sits in shade or under a deck

• A clean, flat surface nearby where you can lay the old cartridge for measuring

You'll also need to shut down the pump and bleed the air relief valve on top of the filter tank before opening the housing. Never open a pressurized filter. Turn the pump off at the breaker or timer, open the air relief valve until water stops hissing, then proceed.

How to Find Your Hayward Pool Filter Model Number

Every Hayward pool filter housing has a product label, usually a silver or white sticker on the tank's side or near the base. This label contains the model number, serial number, and sometimes the replacement cartridge part number. Look for a format like C3030, C150S, or CC10092S.

Decode the Hayward Naming System

Hayward organizes its cartridge filters into families. The model number prefix tells you which series you own. "C" followed by four digits usually indicates SwimClear. "C" followed by three digits often points to Star-Clear or Super-Star-Clear. "CC" models belong to the X-Stream series.

Write down the full model number exactly as printed, including any trailing letters like "S" or "E." Those suffixes indicate generation or regional variants, and they affect which cartridge ships from the factory.

What to Do When the Label Is Gone

Sun and pool chemicals destroy adhesive labels within a few years. If yours is illegible or missing entirely, don't panic. NC State Extension recommends building a detailed equipment inventory with photos of the filter label, model, and installation date to avoid exactly this situation. Going forward, snap a photo the moment you install new equipment.

For now, open the filter tank and pull the old cartridge. The cartridge itself may have a molded part number on the end cap. You can also match by physical dimensions, which we cover next.

How to Measure a Hayward Pool Filter Cartridge

Measuring gets you the answer when labels fail. You need three numbers: overall length, outside diameter, and inside hole diameter. Grab your tape measure and lay the old cartridge on that flat surface.

Overall Length: End Cap to End Cap

Measure from one flat end cap to the other. Include the end cap material itself but exclude any protruding handle, spout, or threaded connector. Common Hayward cartridge lengths fall between 10 and 29 inches. If you're between whole numbers, round to the nearest quarter inch.

Outside Diameter and Inside Hole

Wrap the tape around the widest part of the pleats and divide by 3.14 to get the outside diameter. Most Hayward cartridges measure between 7 and 10.5 inches across. Then measure the open hole at the top and bottom of the cartridge core. This inside diameter determines how the cartridge seats inside the manifold.

A mismatch of even half an inch on the inside hole means the cartridge won't seal properly, so take this measurement carefully.

Hayward Pool Filter Cartridge Size Chart by Series

The table below maps popular Hayward filter families to their cartridge specs. Use your model number or measurements to find your match. For a deeper breakdown of every model variant, the Hayward pool filter replacement guide for 2026 covers the complete lineup.

Square footage should match your housing's rated capacity. A slightly higher sq. ft. rating can work if the physical dimensions match, but going lower restricts flow and shortens filter life.

Hayward Cartridge Filter Replacement: Match by Model or Dimensions

Once you have either your model number or your three measurements, you're ready to find the right cartridge. The fastest path runs through the model number. Search it against the OEM part number column in the chart above, then cross-reference with aftermarket equivalents from Pleatco, Unicel, or Filbur.

For example, a SwimClear C4030 uses the CX880XRE cartridge (sold in sets of four). Compatible aftermarket numbers include Pleatco PA106, Unicel C-7488, and Filbur FC-1226. Atomic Filters carries USA-made replacements for the Hayward CX880XRE that match these specs at a lower price point than OEM.

If you're working from dimensions alone, compare your length, outside diameter, and inside hole measurements against the chart. You need all three to match within a quarter inch. Two out of three isn't good enough.

Aftermarket vs. OEM: What Actually Matters

The 2025 revision of NSF/ANSI 50 clarified minimum cartridge surface area per gallon-per-minute of flow and reinforced labeling requirements for replacement elements. Both OEM and quality aftermarket cartridges can meet these standards. The difference usually comes down to price and pleat count, not safety.

That said, avoid the cheapest no-name cartridges on marketplace sites. Thin media and weak end caps lead to early failure. Stick with brands that publish their filtration specs and stand behind warranty claims.

When to Clean vs. Replace Your Hayward Filter Cartridge

Not every pressure spike means you need a new cartridge. A clean cartridge that's still structurally sound deserves a thorough rinse before you replace it. Hose off the pleats, soak overnight in a filter cleaner solution, and reinstall. If pressure drops back to normal, you've bought yourself another cleaning cycle.

Replace when you see torn or frayed pleats, a cracked or warped end cap, a collapsed inner core, or persistent high pressure after cleaning. Most Hayward cartridges last one to two years with regular hosing and one to two chemical soaks per season. Pools with heavy debris loads or hard water may need earlier replacement.

Understanding how to backwash a Hayward pool filter also helps extend cartridge life in systems that support the process.

Troubleshooting Common Sizing Problems

A few issues come up repeatedly when homeowners try to size Hayward cartridges on their own.

Measurements don't match any chart entry. Double-check that you excluded handles and spouts from your length measurement. Also confirm you measured the outside diameter at the widest pleat point, not at the end cap. If numbers still seem off, your filter may have a previous aftermarket cartridge installed that doesn't match the housing specs. Look up the housing model instead.

Two different cartridges fit the housing. Some Hayward models received mid-run updates that changed cartridge part numbers without changing the housing. The Hayward pool filter replacement size guide covers these overlapping part numbers and clarifies which current SKU to order.

Your filter uses multiple cartridges. SwimClear models use four identical cartridges in a single housing. Replace all four at the same time, even if only one looks worn. Mixing old and new cartridges creates uneven flow distribution and shortens the life of every cartridge in the set.

Frequently Asked Questions

Q: Can I use a single-cartridge replacement on a Hayward housing that originally used a four-cartridge set?

A: No, the internal manifold and flow paths are designed for a specific cartridge count. Using fewer cartridges can cause bypass, poor filtration, and stress on the pump, so you should match the original configuration.

Q: What should I check on the filter housing before installing a new cartridge?

A: Inspect the tank O-ring, the cartridge seating surfaces, and the manifold for cracks, flattening, or debris. A worn O-ring or damaged manifold can cause leaks and make a new cartridge seem like the wrong fit.

Q: How do I know if my filter problems are actually caused by the cartridge and not something else?

A: If pressure remains abnormal after cleaning and reinstalling a known good cartridge, check for issues like closed valves, clogged skimmer baskets, pump strainer blockage, or return line restrictions. Cartridge filters often get blamed for circulation problems that originate upstream or downstream of the tank.

Q: Are there water chemistry habits that help cartridges last longer?

A: Yes, keeping pH, calcium hardness, and sanitizer levels in their recommended ranges reduces scale formation and media damage. Avoiding overuse of flocculants and clarifiers also helps prevent the pleats from gumming up prematurely.

Q: What is the best way to confirm an aftermarket cross-reference number is truly compatible?

A: Compare the aftermarket listing to the OEM part number, then verify fit details like end-cap style, top and bottom opening type, and whether it is open or closed on each end. When in doubt, use the manufacturer spec sheet or contact the seller with your housing model to confirm compatibility.

Q: What mistakes most often cause leaks after a cartridge swap?

A: Common causes include pinched or dry O-rings, dirt on the sealing surfaces, misaligned band clamps, or cross-threaded drain plugs. Lightly lubricating the O-ring with a pool-safe lubricant and cleaning the mating surfaces usually prevents these issues.

Q: How should I store a spare Hayward-compatible cartridge if I buy an extra?

A: Store it clean and dry, out of direct sunlight, and away from ozone generators, solvents, or fertilizers that can degrade plastics and rubber. Keeping it in the original box in a cool garage or indoor closet helps preserve the media and end caps until you need it.

Order Your Replacement With Confidence

You now have a model number or a set of verified measurements, a size chart to cross-reference, and clear criteria for choosing between cleaning and replacing. That's everything you need to order the right Hayward pool filter cartridge the first time.

Atomic Filters stocks compatible replacements for every major Hayward series, manufactured in the USA and backed by thousands of verified customer reviews. Browse Atomic Filters' full Hayward-compatible lineup to find your exact match and save up to 40% compared to OEM pricing, with fast shipping so your pool stays clean without the wait.