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PDC Spas OEM FLT-118 spa filter (PRB7B)
Timeless and XTR
Replacement numbers
Pleatco PRB7B
Fits PDC Spas OEM FLT-118.
Diameter 5" (127 mm)Length 4-5/8" (117 mm)17 sq ft1 model listedSearch this part on Amazon
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| Unicel | not listed in Unicel 2026 guide |
|---|---|
| Pleatco | PRB7B (Deactivated list, PDF p.23: PRB7B, replacement N/A. No PRB7B line in the 2023 spec table. PRB17.5SF-PAIR (PDF p.31) is 5" × 4-5/8", 35 sq ft, and is not named as the replacement.) |
| Filbur | not found in Filbur catalog |
| Top | 2-1/8" (54 mm) / open |
| Bottom | 2-1/8" (54 mm) / open |
Bottom: 2-1/8" (54 mm) / open
Drawn to scale from the listed diameter and length and open-end sizes. Handles, threads and closed ends are drawn as symbols, not to scale. 17 sq ft media.
Timeless and XTR is the group name on the PDC Spas row PRB7B cartridge (OEM FLT-118). Match these numbers: OEM FLT-118; Pleatco PRB7B. 5" across, 4-5/8" long, top 2-1/8" / open, bottom 2-1/8" / open, 17 sq ft.
What the sources add about FLT-118: PDC’s 2025 guide is the only size: Timeless and XTR, 2000–2005, FLT-118, Pleatco PRB7B, 17 sq ft, 5" × 4-5/8", 2-1/8" holes. Pleatco’s 2023 deactivated list prints PRB7B with replacement N/A, and the spec table has no PRB7B row. Unicel’s PDC block lists C-4401 at 35 sq ft, 4-15/16" × 4-5/8", two per set, and does not print FLT-118 or PRB7B. Filbur’s PDC section prints that C-4401 set (FC-2386) and does not print PRB7B. Pleatco does not say PRB7B was replaced by PRB17.5SF-PAIR.
PRB7B cartridge (OEM FLT-118) (OEM FLT-118), Pleatco side: Deactivated list, PDF p.23: PRB7B, replacement N/A. No PRB7B line in the 2023 spec table. PRB17.5SF-PAIR (PDF p.31) is 5" × 4-5/8", 35 sq ft, and is not named as the replacement..
FLT-118, Filbur note: PDC Spas section, PDF p.23 (printed p.45): FC-2386, Rainbow DSF 35, two per set, PRB17.5SF-PAIR/JH, C-4401, 35 sq ft, 4-15/16" × 4-5/8". No PRB7B and no FLT-118..
PDC Spas applications recorded for this cartridge: Timeless and XTR, years 2000–2005, listed by PDC Spas Common Replacement Filter Elements (2025) (FLT-118, Pleatco PRB7B, 17 sq ft. PDC names no Unicel number.).
Before ordering PRB7B, compare it with 4CH-15 differs by Unicel 4CH-15, no Pleatco number, 4-5/8" diameter, 5-3/16" long, top dual bar handle, bottom 1-1/2" SAE, 15 sq ft, OEM FLT-1000-CART, note says PDC’s 2025 guide: XD1, XD1+ and the XD2 cold side, 2024 to present, FLT-1000-CART, 15 sq ft, 4-5/8" × 5-1/4", 1-1/2" SAE on the bottom, bar handle on a closed top, Waterway 817-0020. Unicel’s Waterway line prints 817-0020 as 4CH-15 at 4-5/8" × 5-3/16", dual bar handle, 1-1/2" SAE, 199 pleats, 3 oz, 15 sq ft. The length differs by 1/16". The dimensions on this row are Unicel’s. Pleatco’s 2023 cross-reference has no 4CH-15 and no 817-0020. Filbur’s PDC section does not list it. The XD2 spa side is FLT-171-CART, not this cartridge.; and C-4405 differs by Unicel C-4405, Pleatco PRB25SF-JH-PAIR, Filbur FC-2387, 4-15/16" diameter, 6-5/8" long, 25 sq ft, OEM FLT-171-CART, note says Shown at 25 sq ft because that is what PDC’s 2025 guide prints for the element (LifeStyle, XD2 spa side, and River, 2010 to present), 5" × 6-5/8", 2-1/8" holes, named as Unicel C-4405. Unicel’s OEM cross-reference prints 50 in the square-foot column for C-4405, and the spec note says two cartridges per set. The spec row itself does not print a square-foot figure. Pleatco prints PRB25SF at 25 sq ft for one cartridge and PRB25SF-JH-PAIR at 50 sq ft, and its cross sends C-4405 to the pair. Filbur prints FC-2387 at 50 sq ft, “6 sets,” with the same two-per-set note..
Unicel and Filbur do not have a number on this row. Search FLT-118 or the PDC Spas part you pulled out of the spa.
Left blank on purpose: Pleatco 2023: PRB7B deactivated, replacement N/A, no spec row. Unicel and Filbur list C-4401 at 35 sq ft and two per set for a cartridge of this length, and do not name PRB7B. No Unicel or Filbur equivalent is stored on this row..
Where those figures are printed: PDC Spas (manufacturer filter guide, 2025) on PRB7B (Timeless and XTR, 2000–2005: FLT-118, 17 sq ft, 5" × 4-5/8", 2-1/8" holes, Pleatco PRB7B). Pleatco 2023 Catalog on PRB7B (Deactivated part numbers, PDF p.23: PRB7B replacement N/A). Unicel 2026 Replacement Guide on PRB7B (PDC block, PDF p.47 (printed p.43): C-4401, 35 sq ft, 4-15/16" × 4-5/8". Spec note: two per set. No FLT-118.). Filbur Catalog & Reference Guide on PRB7B (PDC section, printed p.45: FC-2386 = C-4401, 35 sq ft, two per set. No PRB7B.).
Hot tubs listed for this cartridge
The rest of the PDC Spas model list is the PDC Spas filter by model and year lookup.
| Model / system | Years | Listed by |
|---|---|---|
| Timeless and XTR (FLT-118, Pleatco PRB7B, 17 sq ft. PDC names no Unicel number.) | 2000–2005 | PDC Spas Common Replacement Filter Elements (2025) |
Check the cartridge you removed
Measure diameter, length, and both ends, then compare them with the figures above. The steps are in the measuring guide. Why the bottom decides whether it seals: open-end vs threaded filters. Power, the retainer, and not running the spa empty: how to install a cartridge. Number formats: how Filbur, Unicel and Pleatco numbers compare.
Other PDC Spas cartridges
- 4CH-15 cartridge (OEM FLT-1000-CART), 4-5/8" (117 mm) × 5-3/16" (132 mm)
- C-4405 cartridge (OEM FLT-171-CART), 4-15/16" (125 mm) × 6-5/8" (168 mm)
- C-4310 cartridge (OEM FLT-101SK), 4-1/4" (108 mm) × 4" (102 mm)
- C-4326 cartridge (OEM FLT-201TL), 4-15/16" (125 mm) × 13-5/16" (338 mm)
- 4CH-949 cartridge (OEM FLT-SWIM50-CART), 4-15/16" (125 mm) × 13-1/2" (343 mm)
- C-4975 cartridge (OEM FLT-SWIM75-CART), 4-15/16" (125 mm) × 20-1/8" (511 mm)
Every number on this row, on one screen: cross-reference lookup. Published clean and replace intervals for this cartridge, and a buy link for the numbers above: replacement schedule and reorder. The interval comparison by brand: calculator.
Cleaner and test strips
Hose rinse and soak steps are in how to clean a cartridge. Named cleaners and strips are in filter cleaners and test strips.
Filter cleaner and test strips
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Leisure Time O Filter Clean Cartridge Cleaner Listing title: cartridge cleaner, 32 fl oz.
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SpaGuard Filter Cleaner Listing title: filter cleaner for spas and hot tubs, 1 quart.
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AquaChek SPA 6-in-1 Test Strips Listing title: reads total bromine, total chlorine, free chlorine, pH, total alkalinity and total hardness.
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Sources
- PDC Spas (manufacturer filter guide, 2025): Timeless and XTR, 2000–2005: FLT-118, 17 sq ft, 5" × 4-5/8", 2-1/8" holes, Pleatco PRB7B (PDF)
- Pleatco 2023 Catalog: Deactivated part numbers, PDF p.23: PRB7B replacement N/A (PDF)
- Unicel 2026 Replacement Guide: PDC block, PDF p.47 (printed p.43): C-4401, 35 sq ft, 4-15/16" × 4-5/8". Spec note: two per set. No FLT-118. (PDF)
- Filbur Catalog & Reference Guide: PDC section, printed p.45: FC-2386 = C-4401, 35 sq ft, two per set. No PRB7B. (PDF)
Not in sources: Pleatco 2023: PRB7B deactivated, replacement N/A, no spec row. Unicel and Filbur list C-4401 at 35 sq ft and two per set for a cartridge of this length, and do not name PRB7B. No Unicel or Filbur equivalent is stored on this row..