Which filter does my Dimension One hot tub take? Lookup by model and year
If your D1 was built from 2000 on (Reflections, Bay, @Home, AquaFit), it takes the 1561-00 (sold as 01561-00-A): a 75 sq ft, 7-1/8" × 10-1/2" cartridge with a closed castle top and an EZ twist-lock bottom. Aftermarket: Unicel C-7367, Pleatco PDO75-2000, Filbur FC-3059. Reflections and Bay spas hold two filters; @Home spas hold one. Older D1 spas used threaded cartridges that changed almost every year: for example 1561-12 for 1996–2000 Madrid and Barcelona, 1561-02 for 1992–1994 Platinum Series and 1561-05 for many 1991–1993 models. Use the table below.
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The cartridges, with equivalents
| Factory part | What it is | Aftermarket equivalents (catalogs) | Rated area | Our page |
|---|---|---|---|---|
| 1561-00 (01561-00-A) | EZ twist-lock cartridge, closed castle top, 2" open bottom; D1 spas from 2000 on, @Home 2000 and newer. Fits filter screen 01510-501 Pleatco prints 7-1/4" × 10-5/8". | Unicel C-7367 (7-1/8" × 10-1/2"); Pleatco PDO75-2000; Filbur FC-3059 | 75 sq ft | C-7367 |
| 1561-12 | Handle top, 1-1/2" SAE coarse thread; 1996–2000 Madrid and Barcelona, 2000 @Home Hot Tub Outpost gives 7" × 10-5/8". | Unicel 7CH-975 (7" × 10-1/2"); Filbur FC-0475. Pleatco PDO75P3 is on Pleatco’s deactivated list with no replacement | 75 sq ft | 7CH-975 |
| 1561-02 | Handle top, 2" MPT fine thread; 1992–1994 Platinum and other 1993–1994 SL, Ultra and Legend models | Unicel 7CH-752 (7" × 14-3/4"); Filbur FC-0470. Pleatco PTL75XW-F2M is deactivated with no replacement | 75 sq ft | 7CH-752 |
| 1561-10 | Handle top, 2" MPT fine thread; 1995 Platinum Series, 1994 Arena and Diamante | Unicel 7CH-552 (7" × 10-1/2"). Retailers name Pleatco PTL55XW-F2M (deactivated) and Filbur FC-0465 (not in the Filbur catalog) | 52 sq ft (Unicel spec table and two retailers); Unicel’s D1 cross-reference prints 75 | 7CH-552 |
| 1561-05 | Handle top, 1-1/2" MPT fine thread; 1991–1993 models Hot Tub Outpost gives a 4-3/4" diameter. | Unicel 4CH-50 (4-5/8" × 14-3/4"); Pleatco PTL50P-4; Filbur FC-0151 | 50 sq ft | 4CH-50 |
| 1561-14 | Handle top, 1-1/2" MPT fine thread; 1991 and 1993 SRX, Impulse and Duet, 1994–1995 Little Dipper, 1996 Legend | Unicel 4CH-30 (4-5/8" × 11-7/8"); Pleatco PTL25P-4; Filbur FC-0141 | 25 sq ft (Unicel cross-reference, Filbur); 30 in Unicel’s spec table | 4CH-30 |
| 1561-04 | Handle top, 1-1/4" SAE coarse thread; 1996–1998 Little Dipper, 1991 El Nino (also Saratoga Spas) | Unicel 4CH-950 (4-5/8" × 12"); Pleatco PDO-UF25P2; Filbur FC-0173 | 25 sq ft | 4CH-950 |
| 1561-13 | Handle top, 1-1/4" SAE coarse thread. No source we found names the models | Unicel 4CH-940 (4-5/8" × 15"); Pleatco PDO-UF40P2; Filbur FC-0177 | 40 sq ft | 4CH-940 |
| 1561-06 / 1561-07 | Long handle-top cartridge, 1-1/2" MPT. No source we found names the models | Unicel 4CH-65 (4-5/8" × 19-5/8"; Unicel says the original was 23-3/4" overall). Retailers also name Pleatco PTL65H-P4 and Filbur FC-0171, which neither catalog lists | 65 sq ft (1561-06) / 80 sq ft (1561-07) | 4CH-65 |
| 1561-03 | Open both ends (2-1/8"); 1994 Arena, Diamante and Quadra. Discontinued by Dimension One | Unicel C-4340 (4-15/16" × 11-5/8"); Pleatco PMT40; Filbur FC-3081 | 40 sq ft | C-4340 |
| 1561-09 | Ozone cartridge, 12 concentric holes in the top, 2-7/8" open bottom; spas with Crystal Pure water management | Unicel C-5404 (5-1/2" × 17"); Pleatco PDO40-4; Filbur FC-3097 | 40 sq ft | C-5404 |
| 1561-11 | Ozone-style cartridge, 5-1/2" × 11-7/8" (retailer); Retro-fit Vision and Seville only | Unicel C-5402 (discontinued by Unicel, listed without an OEM number). The retailer also names Filbur FC-3096 and Pleatco PDO25-4 | 25 sq ft (Unicel) | not listed |
| 1561-01 (SpaBerry) | Short twist-lock cartridge, closed top with Y stand-offs The 1561-01 number comes from two retailer listings (Leisure Time Inc. and Enjoy Spa Pool); Unicel and Filbur print no D1 number. Filbur prints the length as 5-1/8" and names it “SpaBerry 25” in one table and “Spa Berry 35” in another. | Unicel C-7335 (7-1/8" × 5-7/8"); Filbur FC-3058 | 35 sq ft | C-7335 |
Equivalents and sizes are from the Unicel 2026 Replacement Guide, the Pleatco 2023 catalog and the Filbur catalog, matched on the D1 number. Several older Pleatco numbers are now on Pleatco’s own deactivated list; the table says so. Retailer sizes that differ from the catalogs are noted.
Find your model and year
Dimension One does not publish a filter-by-year chart, and its current owner’s manuals do not print part numbers. The model and year rows below come from Hot Tub Outpost’s product listings for each D1 factory part, checked against SpaStore.com’s D1 listings and the Unicel and Filbur catalogs. For pre-2000 spas these are the least certain part of this page; the number on your old cartridge wins.
| Model | Model years | Filter (D1 part) |
|---|---|---|
| Legend, Californian, Ambassador, Chancellor | 1991 | 1561-05 |
| SRX, Impulse, Duet | 1991 and 1993 | 1561-14 |
| El Nino | 1991 | 1561-04 |
| Californian, Challenger, Legend 1500 Series | 1992 | 1561-05 |
| Platinum Series | 1992–1994 | 1561-02 |
| Arena | 1993 | 1561-05 |
| Californian SL | 1993–1994 | 1561-02 |
| Elite SL | 1993 | 1561-02 |
| Seville SL, Ultra Series, Legend Series | 1994 | 1561-02 |
| Arena, Diamante | 1994 | 1561-03 or 1561-10 (the retailer lists both; see below) |
| Quadra | 1994 | 1561-03 |
| Little Dipper | 1994–1995 | 1561-14 |
| Platinum Series | 1995 | 1561-10 |
| Legend | 1996 | 1561-14 |
| Little Dipper | 1996–1998 | 1561-04 |
| Madrid, Barcelona | 1996–2000 | 1561-12 |
| @Home hot tubs | 2000 | 1561-12 (all 2000 models), or 1561-00 (“2000 and newer”); see below |
| All D1 spas: Reflections Collection, Bay Collection, @Home, AquaFit swim spa | 2000 to current | 1561-00 (01561-00-A), the EZ twist-lock filter |
| Spas with the Crystal Pure water management system | Years not given | 1561-09 (ozone cartridge) |
| Retro-fit Vision, Seville | Years not given | 1561-11 |
How many filters, and how they come out
D1’s own owner’s manuals (2017, 2022 and 2025 editions) say Reflections Collection and Bay Collection spas have two filters: one under the skimmer basket and one under a twist-off lid (the UltraPure filter on Bay models). Each one comes out by twisting it a quarter turn counter-clockwise and lifting it out of its canister, which is the EZ twist-lock bottom of the 1561-00. The @Home manuals describe a single filter cartridge under the skimmer basket. The AquaFit swim spa manual says it has two filters, or three in the AquaFit Plus. All of these manuals recommend cleaning the filters monthly.
Where the sources disagree
- 1994 Arena and Diamante. Hot Tub Outpost lists these models under both 1561-03 (open-ended, 4-7/8" × 11-5/8") and 1561-10 (threaded, 7" × 10-1/2"). The two look nothing alike, so check which style is in your spa.
- 2000 @Home. The retailer says all 2000 model-year @Home tubs used 1561-12, but also says the 1561-00 fits @Home spas from 2000 on. Unicel and Filbur say the 1561-00 is for models dated after 2000. A 2000 tub could have either; look at the bottom of the old cartridge (thread or twist-lock).
- 1561-10 rating. Unicel’s D1 cross-reference rates 1561-10 / 7CH-552 at 75 sq ft; Unicel’s own spec table, Hot Tub Outpost and SpaStore all say 52 sq ft.
- 1561-00 size. Unicel, Filbur and both retailers give 7-1/8" × 10-1/2"; Pleatco prints 7-1/4" × 10-5/8" for PDO75-2000.
- Small size differences on older parts. Hot Tub Outpost gives 4-3/4" for 1561-14 and 1561-05 (Unicel and Filbur: 4-5/8") and 10-5/8" for 1561-12 (Unicel and Filbur: 10-1/2").
- Retired Pleatco numbers. Retailers still cross 1561-12, 1561-02 and 1561-10 to Pleatco PDO75P3, PTL75XW-F2M and PTL55XW-F2M, but Pleatco’s 2023 catalog lists all three as deactivated with no replacement. Use the Unicel or Filbur part instead.
Known limits
- No source we found gives models or years for 1561-13, 1561-06 or 1561-07, or years for the Crystal Pure (1561-09) and Vision retrofit (1561-11) cartridges.
- The pre-2000 model and year list comes from one retailer’s listings and could not be checked against a D1 document.
- The SpaBerry cartridge’s D1 number (1561-01) comes from two retailer listings, not from a D1 document or either catalog.
How to confirm yours
- Read the number on the old cartridge’s end cap and search it here.
- No number? A twist-lock bottom with prongs on top means the 1561-00. Otherwise measure the diameter and length and note the thread (our filter-size guide shows how): 7" threaded cartridges are 1561-12 (10-1/2", SAE thread), 1561-10 (10-1/2", MPT) or 1561-02 (14-3/4").
- See how often to clean a hot tub filter.
Why one cartridge size can carry two different square-foot ratings: our explainer with Unicel’s pleat-count table.
Sources
- Hot Tub Outpost: Dimension One filters category and OEM listings 01561-00, -02, -03, -04, -05, -10, -11, -12, -13, -14 and D1561-09 (models, years, sizes; fetched 2026-10-30)
- Hot Tub Outpost: Dimension One 75 sq ft filter 01561-12 (1996–2000 Madrid and Barcelona, 2000 @Home)
- Hot Tub Outpost: Dimension One 75 sq ft filter 01561-00 (2000 to current, @Home 2000 and newer)
- Hot Tub Outpost: Dimension One 52 sq ft filter 01561-10 (1995 Platinum, 1994 Arena and Diamante)
- Hot Tub Outpost: Dimension One 75 sq ft filter 01561-02 (1992–1994 models)
- SpaStore.com: Dimension One filters (OEM to Unicel, Pleatco and Filbur, sizes)
- SpaStore.com: D1 1561-10 / 7CH-552 listing (52 sq ft, 7" × 10-1/2", 2" MPT)
- Dimension One Spas: Owner’s manuals page
- Dimension One Spas: Bay Collection owner’s manual, 2022 (two filters, quarter-turn removal)
- Dimension One Spas: Reflections Collection owner’s manual, 2017 (two filters)
- Dimension One Spas: @Home owner’s manual, 2022 (single filter cartridge)
- Dimension One Spas: AquaFit owner’s manual (two filters, three in AquaFit Plus)
- Unicel 2026 Replacement Guide: Dimension One Spas cross-reference (printed pp. 29–30) and spec tables
- Pleatco 2023 Catalog: PDO75-2000 spec table; deactivated part numbers (PDO75P3, PTL75XW-F2M, PTL55XW-F2M)
- Filbur Catalog & Reference Guide: Dimension One Spas section
This page summarizes published catalogs and dealer fitment tables; always follow your own spa’s owner’s manual. See our disclaimer and methodology.