Which filter does my Beachcomber hot tub take?

Reviewed November 4, 2026

From 1995 to the present, Beachcomber sells two hot tub filters of the same outside size. SKU 3005845 is 25 sq ft (107 pleats) and SKU 3005815 is 50 sq ft (212 pleats). Both are 4-15/16" across, 13-5/16" long, with a 2-1/8" open core and 3 oz fiber. Unicel lists them as C-4326 and C-4950. Beachcomber does not assign either one to a model name, so the number or the pleat count on the old cartridge decides. A tub from before 1995 takes a different, two-piece spa filter: SKU 3005820 (35 sq ft) or 3005825 (50 sq ft). Beachcomber prints no length for those; Unicel and Filbur size them at 4-5/8" and 6-5/8" long.

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The cartridges, with equivalents

Beachcomber’s stock numbers, outside size, pleat counts and the 1995 split are from Beachcomber’s product pages. Unicel’s 2026 guide is the source of the C-numbers and of the pre-1995 lengths. Pleatco’s numbers are its cross-reference to those Unicel parts; Pleatco does not name Beachcomber. Filbur files the four sizes under Beachcomber without the 30058xx stock numbers.

1995 to present: one body, two areas

Beachcomber’s pages for both current cartridges are headed “For Beachcomber Hot Tubs from 1995 to present.” The 25 sq ft page also says it is approved for tubs manufactured from 1995 to current. Neither page names a model, a series or a year inside that span. The 50 sq ft page says it has double the filtration medium of the 25, and that the tighter pleats strain the water at a finer rate. It does not print a micron rating, and neither does Unicel.

Unicel’s spec note calls C-4950 an upgrade of the 25 sq ft C-4326: same outside size, more media. Beachcomber’s 107 pleats is one off Unicel’s 106. Unicel’s own lookup instructions treat a count within two pleats as a match, so the counts agree for identification, and the pages still print different numbers. Why the same body can carry 25 or 50 sq ft is the pleat count, which is worked out in why same-size spa filters have different square-foot ratings.

Before 1995: a two-piece set, and a different length

Beachcomber’s filtration category titles SKU 3005820 “MICROFILTER 35 SQ (PRE 1995)” and SKU 3005825 “MICROFILTER 50 SQ (PRE 1995).” Each product page says these are generally for pre-1995 tubs, including some older off-brand spas, that use the upfront weir. Each SKU is two pieces. The piece with the blue stem, partly glued in place, goes in first; the piece without the stem goes on top. Beachcomber says to keep two sets, one clean and one ready. Neither page prints a diameter or a length.

Unicel is the catalog that ties the stock numbers to a size: 3005820 is C-4401, 4-15/16" × 4-5/8", 35 sq ft, 4 oz, and 3005825 is C-4405, 4-15/16" × 6-5/8", 50 sq ft, 4 oz. The spec table adds 158 pleats and “2 cartridges per set with stick handle” for both, which matches Beachcomber’s two-piece description. Filbur’s Beachcomber section lists the same two lengths as FC-2386 and FC-2387, “2/set,” at 35 and 50 sq ft. The 50 is longer than the 35. It is not the current 13-5/16" body, and it is not two of the 35s stacked.

Beachcomber’s 3005825 page says the 50 sq ft medium “doubles the amount of filtration capacity.” Against its own 35 sq ft set, 50 is not double. The doubling description matches the current 25-to-50 pair, not this pre-1995 pair. Pleatco, which never names Beachcomber, crosses C-4401 to PRB17.5SF-JH-PAIR and C-4405 to PRB25SF-JH-PAIR, and prints both at a 5" outside diameter rather than 4-15/16". The 35 sq ft JH version also has a 2-3/16" bottom hole in Pleatco’s table, against 2-1/8" on the non-JH pair and on Unicel. If the old set is in your hand, measure it. The filter-size guide is the measuring order, and open-end versus threaded is the fitting check: every Beachcomber cartridge on this page is open at both ends.

Cleaning and replacement

Beachcomber’s 2025 owner’s guide covers tubs manufactured from 1 November 2009. It says to rinse the microfilter once a week, and once a month to soak it 12–18 hours, alternating Filter Cure and Filter Pure, then rinse so cleaner does not go back into the water. Keep two cartridges, one in the tub and one clean. The control’s rCL reminder is every 30 days (clean) and rCH is every 365 days (install a new microfilter). The guide says to put the tub in Standby before the cartridge comes out, so the circulation pump is off while the basket is empty. The product pages say a microfilter can last for years with rinsing and a soak in Filter Soak. That is a longer life than the 365-day reminder. Follow the guide that came with the tub, and treat 365 days as the reminder Beachcomber programmed, not as a statement that the pleats fail on that day.

The same filtration category sells different housings by year, separate from the cartridge: a skimmer lid for 2002 and newer and one for pre-2002, a basket for 2001 and newer, a locking ring for 2001–2008 and another for 2008 to now, and a weir top and bottom for 2001–2008. A cartridge of the right size still will not seat if the weir era is wrong. Those parts are not given dimensions on the category page.

Where the sources disagree

• Pleat count on the 25 sq ft cartridge. Beachcomber prints 107. Unicel prints 106 for C-4326. One pleat, inside Unicel’s ±2 identification rule, and still two printed numbers.
• Outside diameter. Beachcomber, Unicel and Filbur print 4-15/16". Pleatco prints 5" for PRB25-IN, PRB50-IN, PRB17.5SF-PAIR and PRB25SF-PAIR.
• Pre-1995 length. Only Unicel and Filbur print it. Beachcomber describes the set and the weir, not the inches.
• “Doubles the capacity” on SKU 3005825. That page is the 50 sq ft pre-1995 set. The other pre-1995 set is 35 sq ft, which is not half of 50, and Unicel makes the 50 longer, not just denser.
• How long a cartridge lasts. The 2009-and-later owner’s guide sets a 365-day “install new microfilter” reminder. The product pages say a microfilter can last for years.
• No model table. Beachcomber does not say which series takes the 25 and which takes the 50. Both current pages cover 1995 to the present.

How to confirm yours

1. Read the stock number embossed on the cartridge. Beachcomber says it is there for ordering. 3005845 and 3005815 are the long pair; 3005820 and 3005825 are the short two-piece sets.
2. If the number is gone, measure length. About 13-5/16" is the current pair; then count pleats (near 107 is the 25, near 212 is the 50). About 4-5/8" or 6-5/8", in two pieces with a blue stem, is the pre-1995 set.
3. Compare the cartridge in your hand with the Beachcomber cartridge table before ordering an aftermarket number. Pleatco’s 5" diameter is the catalog’s figure, not Beachcomber’s.

Why one cartridge size can carry two different square-foot ratings: our explainer with Unicel’s pleat-count table.

Sources

1. Beachcomber Hot Tubs: Microfilter 25 sq ft, SKU 3005845 (4-15/16" × 13-5/16", 2-1/8" core, 107 pleats, 3 oz, 1995 to current)
2. Beachcomber Hot Tubs: Microfilter 50 sq ft, SKU 3005815 (same body, 212 pleats, 1995 to present, double the medium of the 25)
3. Beachcomber Hot Tubs: Microfilter 35 sq ft, SKU 3005820 (two-piece, generally pre-1995, upfront weir; no length printed)
4. Beachcomber Hot Tubs: Microfilter 50 sq ft, SKU 3005825 (two-piece, generally pre-1995; no length printed)
5. Beachcomber Hot Tubs: filtration parts category (pre-1995 cartridge titles; skimmer lid, basket, locking ring and weir year splits)
6. Beachcomber Hot Tubs: Owner’s Guide, 9 Sept 2025, for tubs built from 1 November 2009 (weekly rinse, 12–18 hour monthly soak, rCL 30 days, rCH 365 days, Standby)
7. Unicel 2026 Replacement Guide: Beachcomber OEM cross-reference, PDF p.29 (printed p.25); spec table C-4401 and C-4405, PDF p.8 (printed p.4); C-4326 and C-4950, PDF p.9 (printed p.5)
8. Pleatco 2023 Catalog: Unicel cross-reference, PDF p.47 (C-4326 = PRB25-IN, C-4950 = PRB50-IN, C-4401 = PRB17.5SF-JH-PAIR, C-4405 = PRB25SF-JH-PAIR); spec table PDF pp.31–32 (5" OD)
9. Filbur Catalog: Beachcomber Spas section, PDF p.15 (FC-2386, FC-2387, FC-2375, FC-2390)

This page summarizes published catalogs and dealer fitment tables; always follow your own spa’s owner’s manual. See our disclaimer and methodology.