Upper & Lower Spa Filter Cartridges - Sapphire, Signature & Others - Top & Bottom
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Upper & Lower Spa Filter Cartridges - Sapphire, Signature & Others - Top & Bottom
- Physically Stocked, unlike most "drop-shipping" websites.
- Shipped from VIC, NSW, WA, QLD
Upper & Lower Swim Spa Filter Cartridge Pair to Suit Sapphire, Signature, Bullfrog & Other Widemouth Front Access Skim Filters
Premium upper and lower replacement filter cartridge pair for many swim spas and large spas using stacked widemouth front access skim filters. Commonly found on selected Sapphire, Signature, Spa Industries, Bullfrog, V-Stream, and other brands using this upper/lower cartridge style.
We also stock the Microban version of this upper and lower filter pair.
This filter set uses a stacked top and bottom cartridge design. The upper filter has a closed top with handle and a smooth lower spigot that fits into the lower cartridge. The lower filter has an open crown top and a coarse ACME-style threaded spigot on the bottom. This style is commonly used in Waterway front access skim filter housings and similar wide mouth systems.:contentReference[oaicite:1]{index=1}
Common Part Numbers / Cross References
- SS50T - upper cartridge
- SS50B - lower cartridge
- FC-SS50T
- FC-SS50B
- SG100
- RFIL15050M
- RFIL15050F
- AFILK25MFS
- MSG100-K
- Unicel 6CH-942
Commonly Suits
- Sapphire swim spas and portable spas using stacked widemouth filters
- Signature spas using this upper / lower filter pair
- Spa Industries swim spas using this filter style
- Bullfrog swim spas using the widemouth stacked cartridge arrangement
- Waterway front access skim filter housings
- Selected V-Stream and other re-branded systems using the same dimensions and end configuration
Specifications / Dimensions
- Sold As: 1 x upper filter + 1 x lower filter
- Combined Height: approx. 425mm or 460mm overall, depending on version, excluding handle and threaded spigot
- Upper Filter: approx. 210 to 225mm height x 145 to 150mm outside diameter x closed top x 44 to 53mm smooth lower spigot
- Lower Filter: approx. 220 to 225mm height including crown x 145 to 150mm outside diameter x open crown top at approx. 44mm ID x 47 to 50mm coarse threaded lower spigot
- Top / Bottom Design: upper locks or slips into lower depending on version
100 sqft and 200 sqft Skim Filter Applications
These cartridges are commonly used in front access skim filter housings with two stacked cartridges. In many systems, one pair is used for 100 sq ft housings and two pairs are used for 200 sq ft wide mouth housings.:contentReference[oaicite:2]{index=2}
Quality Matters
These are not cheap low-grade marketplace filters. They are quality replacement cartridges made using USA-made Reemay or Darlly filter media for reliable water flow, solid dirt-holding capacity, and consistent performance. Cheap filters often use poorer media, fewer pleats, and weaker end caps, which can reduce cleaning performance and service life.
Important Before Ordering
- Please compare the photos, measurements, top style, and bottom connection carefully before ordering.
- The male / female spigot connection is intentionally a tight fit. If needed, warming the parts slightly can help them fit together properly.
- Some newer versions are slightly shorter overall but use more pleats to maintain similar filtration area.:contentReference[oaicite:3]{index=3}
- Many spas use similar-looking filters, so fitment should always be confirmed by dimensions and end style, not by spa brand alone.
Premium Quality. Trusted Brands. No Gimmicks.
Heater & Spa Parts supplies premium-grade pool and spa cartridge filters. Unless otherwise stated on the individual product listing, our replacement cartridges are supplied by leading filter manufacturers including Magnum® and Darlly®, using high-quality filtration media such as Reemay®, Darlly® media, Pleatco® media or equivalent premium-grade material.
Not sure which filter you need?
Use our Filter Finder to search by dimensions, model or cartridge number.
Magnum and Darlly are established specialist cartridge-filter manufacturers supplying replacement and OEM filtration products throughout the pool and spa industry. Major equipment and spa brands generally do not manufacture their own cartridge elements. Instead, cartridges are commonly produced by specialist filtration manufacturers to suit the required housing, dimensions and filtration specifications.
Their products are used across equipment from brands including AstralPool, Balboa, Davey, Emaux, Halo Spas, Hurlcon, Madimack, Oasis Spas, Sapphire Spas, SpaNet, Spa World, Vortex®, Waterco, Zodiac and many others.
Because we purchase filters in significant volumes, we can offer recognised premium filter brands at competitive pricing without relying on cheap, unidentified generic cartridges commonly found through marketplace sellers.
Why filter quality matters
A cartridge filter needs to maintain water flow while trapping fine debris without the media prematurely collapsing, separating or shedding fibres.
- Quality filtration media with consistent pleat construction
- Strong end caps and centre cores
- Better resistance to repeated cleaning cycles
- Reduced risk of premature fibre shedding or media failure
- Reliable filtration without unnecessarily restricting water flow
Cheap cartridges can look almost identical when new, but differences in media quality, pleat construction, bonding and internal support can significantly affect service life and filtration performance.
NSF® and recognised filtration materials
Many premium filtration materials and cartridge ranges from manufacturers such as Darlly®, Magnum®, Pleatco® and Reemay® are manufactured using materials tested or certified to recognised filtration and water-industry standards. Where a specific NSF® certification applies to a product, media or material, this should be considered in conjunction with the manufacturer's specifications for that particular cartridge.
How to clean a cartridge filter
Clean the cartridge when:
- Spas: water flow or jet pressure noticeably reduces.
- Pools: filter pressure rises approximately 35 to 45 kPa above the normal clean-filter pressure, unless the equipment manufacturer specifies otherwise.
Cleaning procedure:
- Switch the filtration system off and remove the cartridge according to the equipment manufacturer's instructions.
- Rinse loose debris from between the pleats using a garden hose.
- Periodically soak the cartridge in a purpose-made cartridge filter cleaning solution to remove oils, lotions and accumulated contamination.
- Rinse thoroughly after soaking.
- Reinstall the cartridge carefully and ensure all seals, lids and locking components are correctly seated.
Important:
- Do not use a pressure washer or high-pressure nozzle on cartridge media.
- Do not aggressively scrub the pleats with a hard brush.
- Avoid flocculants and excessive use of clarifiers with cartridge filters.
- Maintain correct water chemistry to maximise cartridge life.
When should a cartridge filter be replaced?
There is no single replacement interval that applies to every pool or spa. Cartridge life depends on water chemistry, operating hours, contamination, cleaning frequency and how heavily the system is used.
As a general guide, many cartridges are replaced approximately every 12 to 24 months, but replacement should be based primarily on condition and performance.
Replace the cartridge if you notice:
- Torn, frayed or separating filter media
- Cracked or damaged end caps
- Collapsed or badly distorted pleats
- Persistent poor flow even after proper cleaning
- Contamination or staining that cannot be removed
- The cartridge no longer returns to normal operating pressure after cleaning
Warranty
Unless otherwise stated, our standard cartridge filters are covered by a 12-month replacement warranty against manufacturing defects in materials or workmanship. Disposable cartridges and filters used in inflatable spas may have different warranty conditions. Damage caused by incorrect installation, misuse, excessive pressure, chemical damage, poor water chemistry or improper cleaning is not considered a manufacturing defect.
Why buy your filter from Heater & Spa Parts?
- Recognised filter manufacturers including Magnum® and Darlly®
- Premium Reemay®, Darlly®, Pleatco® or equivalent filtration media where specified
- Thousands of replacement applications across pool and spa equipment
- Competitive pricing through high-volume purchasing
- Dedicated online Filter Finder to help identify the correct cartridge
- Real pool and spa parts knowledge if you need help identifying an unusual filter
Buy the correct filter once. Match the dimensions, end configuration and cartridge number carefully before ordering, and use our Filter Finder if you are unsure.
How to Measure a Pool or Spa Cartridge Filter
If you do not know the exact filter model or part number, measuring the existing cartridge is usually the easiest way to identify the correct replacement. You will need a few basic measurements, preferably in millimetres (mm).
Looking for the correct replacement filter?
Use our Filter Finder here to search by filter dimensions, model or cartridge number.
Measure as accurately as possible, but allow for a small amount of variation between an old cartridge and a new replacement. As a general guide, dimensions within approximately 5% may still indicate the same filter, particularly where an old cartridge or filter body has expanded, compressed or distorted with use.

1. Total length
Measure the main body length of the cartridge. Generally, do not include a handle, locating spigot or threaded connection unless the filter listing specifically requires that measurement.

2. Outside diameter
Measure straight across the widest part of the cartridge. This is the outside diameter of the filter.

3. Hole or spigot diameter
Spigot: If the cartridge has a male locating spigot or male threaded connection, measure the outside diameter of the spigot or thread.
Hole: If the cartridge has an open hole rather than a spigot, measure the inside diameter of the hole.

4. End connection type
The end connection is just as important as the overall dimensions. Common cartridge filter connections include:
- Open hole
- Fine thread
- Coarse thread
- Male spigot
- Camlock or bayonet-style fitting

Before ordering, check all four:
- Overall cartridge length
- Outside diameter
- Hole or spigot diameter
- End connection or thread type
Still unsure? Use our Filter Finder to narrow down the correct replacement from your measurements.
SS50T + SS50B
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