MSG100-K Signature / Sapphire Swim Spa Upper & Lower Skim Filter Cartridge Pair - 100 sqft
MSG100-K Signature / Sapphire Swim Spa Upper & Lower Skim Filter Cartridge Pair - 100 sqft is temporarily out of stock and will ship as soon as it's available.
Don't Guess - Ask Us!
Don't Guess - Ask Us!
Not sure if it’s the right part? Send us a message and a photo of what you’re replacing, or what you need, and we’ll help make sure you get the right part the first time.
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MSG100-K Signature / Sapphire Swim Spa Upper & Lower Skim Filte...
MSG100-K Signature / Sapphire Swim Spa Upper & Lower Skim Filter Cartridge Pair - 100 sqft is temporarily out of stock and will ship as soon as it's available.
Spatex MSG100-K Signature / Sapphire Swim Spa Upper & Lower Skim Filter Cartridge Pair - 100 sqft
Spatex MSG100-K upper and lower replacement filter cartridge pair, made in New Zealand by Magnum Filters. This stacked top and bottom set suits swim spas and large spas using widemouth front access skim filters, including selected Sapphire, Signature, Spa Industries and Bullfrog models. Supplied as one upper plus one lower.
- Physically Stocked, unlike most "drop-shipping" websites.
- Shipped from VIC, NSW, WA, QLD
Spatex filter cartridges are manufactured by Magnum Filters in New Zealand. Magnum have been producing spa and pool filter cartridges since 1982 and supply OEM and co-branded cartridges to spa manufacturers and distributors worldwide. These are not low-grade generic filters - they use quality pleated filtration media for reliable water flow, solid dirt-holding capacity and consistent service life, and are used throughout the Australian spa industry alongside WWDG and SpaPro style filters.
Specifications
- Sold as: 1 x upper cartridge plus 1 x lower cartridge
- Combined height: Approximately 425mm or 460mm overall depending on version, excluding handle and spigot
- Upper cartridge: 210mm to 225mm high x 145mm to 150mm OD, closed top, 44mm to 53mm smooth lower spigot
- Lower cartridge: 220mm to 225mm high including crown x 145mm to 150mm OD, open crown top at approximately 44mm ID, 47mm to 50mm coarse threaded lower spigot
- Filter area: 100 sqft combined
- Spatex part number: sx-sg100-k
- Magnum part number: MSG100-K
- Country of manufacture: New Zealand
Also Known As
This cartridge is sold under a number of OEM, distributor and aftermarket part numbers, including: MSG100-K, SG100, SS50T, SS50B, FC-SS50T, FC-SS50B, RFIL15050M, RFIL15050F, AFILK25MFS, Unicel 6CH-942, 817-0011.
Commonly Suits
- Sapphire swim spas and portable spas using stacked widemouth filters
- Signature spas using this upper and lower pair
- Spa Industries swim spas using this filter style
- Bullfrog swim spas with the widemouth stacked arrangement
- Waterway front access skim filter housings
- Selected V-Stream and rebranded systems with the same dimensions
Spa brand alone is not enough to identify a filter. Manufacturers frequently change filtration systems between models and production years, so always compare your existing cartridge before ordering.
Before You Order
One pair is generally used for 100 sqft housings and two pairs for 200 sqft widemouth housings. The male and female spigot connection is intentionally a tight fit - warming the parts slightly helps them seat together properly.
Measure the overall length, the outside diameter, the top style and the bottom connection and compare them against this listing. If you are unsure, send us a photo and the measurements of your old cartridge and we will confirm the correct replacement.
Filter Replacement Guide
Spa filters should generally be replaced every 1 to 2 years, depending on usage, water quality, chemical balance and cleaning routine. Rinsing the pleats regularly and soaking the cartridge in a dedicated filter cleaner will extend its working life between replacements.
To the layperson, plumbing sizes and their names can be confusing due to the nominal sizes and naming conventions used.
This is not something we made up. Plumbers and manufacturers have used nominal (meaning ‘by name only’) sizing for decades.
Simply put, in plumbing, named sizes are often not the actual measurements of the pipe, fitting, or part. A PVC pipe called “50mm” or “2"” does not measure 50 mm anywhere. Instead, it follows nominal sizing, an internationally-standardised naming system.
Almost all fittings we use in the pool & spa industry use “pressure PVC” pipe & fittings. Do not confuse with “DWV” or other pipe & fittings and their names and sizes.
Use the Outside Diameter (OD) to check your pipe against fittings. Below is a quick reference for common spa & pool pipe sizes:
| Imperial Name | Metric Name | Pipe Diameter (OD) |
|---|---|---|
| 1/2" | 15mm | ~21.2–21.5 mm |
| 3/4" | 20mm | ~26.6–26.9 mm |
| 1" | 25 mm | ~33.4–33.7 mm |
| 1.5" | 40 mm | ~48.1–48.4 mm |
| 2" | 50 mm | ~60.2–60.8 mm |
| 2.5" | 65 mm | ~75.2–75.5 mm |
To reiterate, these are nominal sizes and are designed to fit matching fittings — not to measure what their name suggests. These are based on PVC Pressure Pipe AS/NZ 1477 Dimensions1.
- º Internal diameters vary slightly by manufacturer and class.
- 1 Not all pool/spa fittings match these dimensions exactly. Some do not follow Australian or international standards. Chinese spas may use proprietary fittings.
Understanding Plumbing Sizes & Nominal Measurements
Plumbing sizes can be confusing. PVC and many other pipe systems use nominal sizes—the size is a name, not the exact measured dimension. This convention is used across most pool and spa systems and other plumbing areas so that pipes and fittings remain compatible.
Why pipe sizes don’t match the measurements
The Nominal Pipe Size (NPS) system standardises pipe dimensions so that pipes, fittings, valves, and accessories interoperate.
Plumbers work with these nominal names every day, but DIYers can be tripped up if they try to match by a tape-measure alone.
How to Measure Pipe Correctly
-
Pipe size is identified by:
- The pipe’s Outside Diameter (OD).
- The fitting’s Inside Diameter (ID) (socket opening).
- Pipe Class / Schedule (e.g., Class 9, 12, 18 or Sch 40) relates to wall thickness and therefore the Internal Diameter (ID) and pressure rating.
- The outside diameter of a fitting is not useful (wall thickness varies by manufacturer).
Hose & Tube Dimensions
Common flexible hose sizes used in pool/spa systems (approximate IDs).
| Imperial Name | Metric Name | Inside Diameter (ID) |
|---|---|---|
| 3/8" | 9–10 mm | ~9 mm |
| 3/4" | 19 mm | ~19 mm |
BSP – British Standard Pipe Thread Sizes
BSP thread names are also nominal. The thread OD will not equal the nominal name.
| BSP Thread Size Naming | Outside Diameter (mm / inch) | TPI |
|---|---|---|
| 1/16" BSP | 7.7 mm / 0.304" | 28 |
| 1/8" BSP | 9.7 mm / 0.383" | 28 |
| 1/4" BSP | 13.16 mm / 0.518" | 19 |
| 3/8" BSP | 16.66 mm / 0.656" | 19 |
| 1/2" BSP / 15 mm | 20.99 mm / 0.825" | 14 |
| 5/8" BSP | 22.99 mm / 0.902" | 14 |
| 3/4" BSP / 20 mm | 26.44 mm / 1.041" | 14 |
| 7/8" BSP | 30.20 mm / 1.189" | 14 |
| 1" BSP / 25 mm | 33.25 mm / 1.309" | 11 |
| 1-1/4" BSP | 41.91 mm / 1.650" | 11 |
| 1-1/2" BSP / 40 mm | 47.80 mm / 1.882" | 11 |
| 2" BSP / 50 mm | 59.61 mm / 2.347" | 11 |
| 2-1/4" BSP | 65.71 mm / 2.587" | 11 |
| 2-1/2" BSP | 75.18 mm / 2.960" | 11 |
| 3" BSP | 87.88 mm / 3.460" | 11 |
| 4" BSP | 113.03 mm / 4.450" | 11 |
| 5" BSP | 138.43 mm / 5.450" | 11 |
| 6" BSP | 163.83 mm / 6.450" | 11 |
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